This was scanned from a small notebook of my poetry:
Thursday, September 02, 2021
Wednesday, September 01, 2021
Puppet Props - Cuckoo Clock
The sticks at the bottom are part of the support system. I split a photo of the clock three times (into 8 equal parts of about 8.5 x 11 inches each) to make it about 22 x 34 inches. The parts were pasted onto foam-core board, and to counteract curling of the board, blank paper was pasted on the back side. The shape was cut out and the edges colored brown to hide the white color of the foam core.
A double door 4.5 inches wide and high was cut into the area above the clock face. The hinge areas were reinforced with clear plastic packing tape. The cuts for the door were widened a bit to eliminate friction on the door edges. A puppet bird can push the doors open, and when the bird withdraws, the doors are pulled closed by a weighted string.
Here are two views of the back side:
Popsicle sticks were glued on the back to strengthen some narrow areas. Two wire hooks with attached wood sticks enable the clock to hang on the top rail of the puppet stage in front of the top curtain. The big sticks go down between the top curtain and the top script rail, preventing the clock from tipping forward, especially when a puppet bird thrusts its head through the door. (A script rail holds a row of four open three-ring binders across the 7-foot width of the stage.)
The vertical narrow box between the two big sticks encloses the weights that pull the doors closed. This box and the foam-core ridges on either side of the two big sticks push the clock away from the top rail and the top curtain so that the top rail and curtain do not interfere with the rise and fall of the weights. More details on the door-closing mechanism next.
The next views show the doors held open by a tissue box:
Each door has a wire taped to its back side, but extending on the outside about two inches below the door. A string attached to each wire passes through a grommet hole on one side of the "XII" of the clock face. These two strings are actually the ends of one loop of string from which the weights hang. Thus the weights pull equally on both doors, whether one is open or both.
The next view shows a few other details:
You can see the string loop from the grommets going into the box that allow the weights to slide freely without pressure or friction from the stage curtain. You can also see the heavy wire pieces that anchor the top of one of the wire hooks that hang on the top rail of the puppet stage. The wire loop that passes through the foam core board is painted brown on the front side. The colored paper on the back of each door covers the wire that is taped onto the back of the door.
Automatic Garden Watering Systems
From Automatic Garden Watering Systems |
From Automatic Bird Bath |
From Automatic Garden Watering Systems |
From Automatic Garden Watering Systems |
From Automatic Garden Watering Systems |
The main line is a stiff black hose about the same size as regular garden hose, running behind the trellis behind the herb garden. (The trellis hides an air conditioning compressor and some garbage cans.) Here is a view behind the trellis:
From Automatic Garden Watering Systems |
The main line hugs the wall on the left, and quarter-inch hoses are connected to the main line. A hole is punched in the main line, and a flow-control button is plugged into the hole. You can get buttons for different flow rates such as 0.5, 1, or 2 gallons per hour. For example, at 1 gal/hr, dripping for 4 minutes will deliver about 1 cup of water at a designated spot.
Using a T connector, I joined two buttons to one hose to burrow under the stones and then go through the lattice to the herb bed. After going through the lattice, another T connector divides the flow to reach two drip locations. This pattern is repeated several times along the length of the lattice and herb bed.
Tuesday, July 30, 2019
How to Make an Automatic Bird Bath
In a previous blog, I briefly described my Automatic Bird Bath, and I will give more details here, especially how to make one.
Controlled by a timer, any debris accumulated during the day (fallen from trees or left by birds) is flushed out of the bowl of the bird bath at the end of the day. I recommend setting the time to late in the evening when it is highly unlikely that a bird will be using it. We don't want a bird to be suddenly and forcefully swept out while bathing!
The force of the flushing operation will leave the bowl nearly empty; but overnight, the dripper will refill the bowl. During the day, the dripper will not only make a sound that advertises a source of water for the birds, but will also keep the bowl filled as the sun evaporates the water and as the birds splash some of the water out.
The next photo views the bird bath from the side, labeling some of the parts. We will detail the hardware parts later.I have supported the parts with a "shepherd's crook" pole, the kind typically used to support a hanging flower pot. But the bent "crook" is not used, so any sturdy pole will do.
A bent metal strap is fastened to the pole with U-hooks U1 and U2, and to the hose with U-hooks U3 and U4. The hose is a sturdy watering hose, The usual male connector at the end of the hose is removed by cutting the hose with a hack-saw. Clamp C flattens the end of the hose so that the water comes out as a flat, fan-shaped spray. Before you adjust the angle and position of the bent metal strap, you should experiment with this fan-shaped spray to find the best angle and position of the hose to sweep out the bowl, tossing some debris into the bowl as part of the test.
The dripper D is just quarter-inch hose, the kind used for drip watering. The drip hose is fastened to the pole with twist-ties or plastic tape. The valve V in the photo is used to adjust the drip rate. You can buy the valve from places that sell drip watering parts. The part of the drip hose that arches from the pole over the center of the bird bath needs to be stiffened. I wrapped wire around a wood dowel to make a spiral, which I slipped over the drip hose. One end of the same wire that was not wrapped around the dowel was wrapped around the pole to anchor the drip hose. The drip hose should be high enough to give large birds enough room for splashing. Then bend the stiffened part of the drip hose so that it will drip near the center of the bowl.
The hardware parts are shown in the next diagram. I bought one-inch wide steel material as thick as a typical steel hinge at a hardware store and cut it to the lengths indicated here. I bought the U-bolts and small straps used with them as-is at the hardware store. The U-bolts must be large enough to fit around the watering hose, and this will generally be large enough to fit around the pole.
The long strap must be bent on an angle at its center. The angle is needed so that the hose can pass by one side of the pole. To assure yourself of the correct angle, make a 'dummy' strap of cardboard, then hold the hose at the desired angle alongside of the pole, and bend the 'dummy' strap so that one half is parallel to the pole and the other half is parallel to the hose. Note the angle of the bend (about 50 degrees) and how far it is bent (about 80 degrees).
Use a sturdy vise mounted on a work bench to bend the strap. Mark the location and angle of the bend, and clamp the strap in the vise with the bend line at the edge of the vice jaws. Then hit the strap near the bend line with a hammer until it is bent the right amount by your best estimate. You can adjust this later.
The short strap can be bent by a similar method. I recommend drilling the holes after bending, as this will make it easier make the holes aligned. Here it is more important that the bend is centered, so that the two ends will come close together. So reversing the strap in the vice after partly bending it can help. Also, because the strap will wrap around a partly flattened hose, we don't want the bend the strap too sharply. Clamping a big nail or small bolt alongside the strap near the edge of the clamp will promote a 'softer' bend (more like a U, less like a V). Try how it fits over the end of the hose, flattening the hose, but not so much that water flow is shut off. Drill a hole through both ends of the strap large enough for a bolt to go through the holes. The short strap should not be bent too much; the two sides should be about 1/2 inch apart, and it should need the bolt and a nut to pull the strap a little more to make the two sides of the strap parallel on either side of the flattened hose.
Here are the controls. A Y-connector divides the water supply for the flushing function and for the dripper.
The flushing is controlled by a water timer to turn on at 10 pm so no birds will be flushed out of the bird bath. Three seconds is sufficient to flush the bird bath, by most water timers cannot be programmed for intervals that short, so it is set for the shortest possible interval (one minute). When on, the water flows at full pressure.
Drip systems are not designed to operate at full water pressure. So on the right side of the Y-connector, we have a pressure reducer and an adapter that adapts the 3/4 inch hose hardware to the 1/4 inch drip hose. You can also insert a flow-control button in the 1/4 inch drip hose line. These can be bought where drip system parts are sold.
My bird feeders and bird bath are at the back edge of my back lawn, near scrubs and trees, an ideal location because birds want a place that feels safe from predators, at the boundary of a place to hide in foliage (but close enough to look for an opportunity to visit the feeders or bath) and an open area to flee if needed. Because it is near trees, the bath tends to collect debris from the trees; and because the water supply and controls are near the house, the flush and drip hoses must cross the lawn.
My method of burying a hose under a lawn is fast and simple. I thrust a flat shovel as deep as I can into the grass, and tilt it forward and back to wedge open a narrow trench, repeating this along a mostly straight line. Then I push the hose down into the trench as far as I can, using a broom handle or long scrap of 3/4 inch lumber. Then stepping on either side of the trench pushes the grass back into place, closing the crevice. Within a week, all evidence of the crevice will disappear. Winter freezing is not a problem when the water is turned off, because the hose is soft, not rigid like metal pipes.
I have acquired 45 patents during my 43-year career, all of which are expired by now. But in my retirement, I am too lazy to file for a patent for my automatic bird bath. I know how much work it takes, even with the help of a patent lawyer. I have preferred to put it in the "public domain" for any one to use.
Not everyone has the tools and muscle to make the straps. But if you are willing to make these or more parts of my design for others, leave me a comment with your contact information, and I will publish it here. But I won't get involved with any financial arrangements.
One reader of this blog makes and sells his own patented design, which automatically cleans and refills, but does not include a dripper. See http://selfcleaningbirdbath.com/ .
Tuesday, February 19, 2019
The Ingraham Circus
Now it may seem silly, but I feel that a review of basic English grammar is needed before I proceed.
English has nouns and adjectives. "Women" is a noun. "Transgender" is an adjective. "Transgender Women" are women that are transgender. People that are described as transgender are invariably confused about their gender. So "transgender women" means gender-confused women. In normal English, that is.
But when Laura Ingraham said that transgender women were a trouble in women's sports, I suspected that something was wrong, because I knew it was the transgender, that is, gender-confused men that were making trouble in women's sports. It soon became apparent that Laura was speaking in Gender-confused English.
In Gender-confused English, the word 'transgender' is a special adjective that triggers novel rules of grammar never seen before in the long history of the English language. It has the power to reverse the gender of any noun to which it is attached. Moreover, it has the power to not only modify the grammar of sentences, but even paragraphs, because the gender of all pronouns that refer to such a gender-reversed noun must likewise be reversed. In short, when you speak Gender-confused English, you sound like you are pretending to be as confused as the transgender people you are talking about.
The show became more interesting, astounding I thought, when Laura began to interview Martina Navratilova on the subject. Martina was speaking normal English while Laura spoke in Gender-confused English, one saying "men" and the other saying "transgender women" to refer to the same trouble-makers. They must have understood each other in spite of this, because they acted like they heartily agreed. It was quite a circus, more entertaining than the traditional bearded lady.
Thursday, February 14, 2019
How do you write "Jim Clark" in Chinese?
He said that they find Chinese words that sound like the name, and combine them. He thought for a minute, and thought of Chinese words that sounded to me like 'jin', 'kar', and 'lok'. He told me what the words meant, but I forget, except that one meant a small dish used for offerings to idols. He wrote it on the blackboard, and I asked him to teach me how to write it.
He told me to first see each stroke in my head, then write it with a quick, chopping motion. I memorized it, practiced it, and wrote it on a small slip of paper so that I would not forget it.
About a week later, a couple of engineers were in my office, and we started talking about languages. I told them that I knew a few words of German, Greek, and Latin, and that I could write my name in Chinese. They said that they could believe me about the German, Greek, and Latin, but about the Chinese, I was a bragging liar.
I protested, "no, I really can". I wrote it on the blackboard with quick, confident strokes. They still did not believe me.
They said, "It LOOKS like Chinese, but it is fake. We can prove that you are a liar. We will go get an expert." They left the room, and a minute later came back with their 'expert'.
As they entered, I saw that the 'expert' was my Chinese friend. He gave me a quick smile when they were not looking.
"Don't say one word", they warned me. Then pointing to what I had written on the blackboard, they asked the expert, "What does that say?"
He answered, "It means Jim Clark", and their mouths dropped open. Then my Chinese friend and I laughed, and we explained how he had taught me a week ago.
Unfortunately, I have lost that small slip of paper with my name written in Chinese.
Does someone know Chinese well enough that they can tell what "Jim Clark" looks like, as my friend probably told me?
Friday, January 04, 2019
The Geometry of the Times Square Ball
It is described as having "a diameter of 12 feet and weighing 11,575 pounds" and is "covered with 2,688 Waterford Crystals", also called "triangular crystal panels". It has a total of "32,256 Philips Luxeon Rebel energy-saving LEDs", and from this I figured that there are 12 LEDs per triangular crystal panel.
There are 672 "LED units", each having 48 LED lights, 12 each of "red, blue, green and white colors". 672 times 48 is 32256, confirming the total LEDs. We can also conclude that each "LED unit" has 4 triangular crystal panels, because there are 12 LEDs per crystal panel.
In the photo of the Times Square Ball, we can see triangles framed by the black aluminum struts; we will call these 'frame' triangles. Each frame triangle is divided into four 'color' triangles which apparently have independently selectable colors. And if you look carefully, each color triangle is divided into four 'tiny' triangles. So which of these triangle sizes is a "crystal panel"?
Geodesic spheres are nearly always based on the geometry of an icosahedron, generally by dividing its triangular faces into smaller triangles. There are 20 triangles in a icosahedron; 12 vertices, and 30 edges, and 5 edges meet at each vertex. A typical geodesic sphere is full of triangles, and in most places, a cluster of six triangles around a vertex form a hexagon. But in rare places, a cluster of five triangles around a vertex will form a pentagon.
Finding these pentagons is the trick to discovering the icosahedron from which the geodesic sphere was formed, because the centers of these pentagons are the vertices of the icosahedron. You can impress your friends by 'counting' the number of triangles in the complete 'sphere' that you see (even though it is not actually complete or not all visible) in two or three seconds, as follows: Find two pentagons and along the line that connects their centers, count the number of edges of the small triangles. Square this number and multiply by 20. That's it. If you counted 10 edges, the answer is 10x10x20=2000. In a few seconds, you have 'counted' 2000 triangles!
So we conclude that each color triangle corresponds to an LED unit, which has 48 LED lights. And each tiny triangle must correspond to a Waterford crystal panel, which has 12 LED lights, 3 LEDs of each color, which can be neatly arranged in a triangle. I have seen a number of products using LEDs which embed LEDs in a plastic sheet to distribute the light over the area; so I guess that LEDs are similarly embedded in the Waterford Crystals.
We have been ignoring one small but interesting detail. When a flat triangle of an icosahedron is divided into smaller triangles (144 Waterford Crystals in this case) by dividing the edge length by an integer value (12 in this case), the big triangle remains flat. What is actually done is that the smaller triangles are made a tiny bit larger; making the big triangle bulge out just enough so that all the triangle corners (vertices) lie perfectly on a spherical surface; which is how geodesic spheres look almost like real spheres. The calculation of this adjustment involves trigonometry; need I say more?
Friday, June 01, 2018
Trellis Project
The Situation
When a former owner of my house decided to add an extension at the back, he decided to minimize the cost by using a corrugated plastic material for the side wall of the unfinished space below the new master bedroom. Over the years, this material became grimy-looking, which became more evident when new siding was put on the house.The Plan
I didn't want to paint this wall, because the material is translucent, and allows daylight to illuminate the storage and shop area inside. Instead, I decided to hide the ugly wall and the air-conditioner compressor behind a trellis. Garbage cans could also be hidden behind the left side of the trellis. This was also an opportunity to make a raised bed for an herb garden. The trellis would rest on the back edge of the raised bed. Clematis could also be planted in the raised bed and allowed to climb on the trellis. Hinged 'gates' at either end of the trellis would allow access to the garbage cans and to the AC compressor. (The white space at the bottom right of the diagram represents the neighbor's fence.)Phase One
The first phase was to re-locate the step-stones further away from the house and to re-shape the lawn edge to make two 45-degree turns instead of one 90-degree turn. The white stones were washed, and new weed-stop fabric was installed under the white stones and step-stones.Phase Two
The second phase was to build the raised bed for the herb garden, filling the bed (including two feet deep below ground level) with good loam-rich soil mixed with plenty of sand for good drainage.Phase Three
The last phase was to build the trellis, fastened to the back edge of the raised bed, and kept from tipping over by braces fastened to the bottom of the siding.. Notice that the holes in the trellis are larger at the top and sides. Next, we will describe this phase in more detail.Pre-assembly
The frames of the various panels were pre-assembled from 2-by-3-inch lumber and painted before the final assembly. There is no pre-assembled frame for the narrow center panel because it is just the space between the two wide panels. (It only needs top and bottom frame pieces.)After painting, the vinyl channel strips were screwed onto the wood frames, holding the vinyl trellis panels in place. The channels are supposed to allow for the expansion and contraction of the vinyl trellis panels due to temperature changes. But adjusting the channel positions is tricky: Where is the current temperature relative to the minimum and maximum temperatures?
Tip-over Bracing
The trellis is kept from tipping over by braces (made of 3/4-by-2-inch wood) fastened to the top of the trellis and the bottom of the siding on the house, as shown here.The Center Panel
The Gate Hinges
Each gate is allowed to turn inward by 45 degrees by rip-cutting a 2-by-3-inch piece of lumber on a diagonal, making two 22.5-degree wedges, and adding a wedge to the hinge side of each frame. This photo also shows the ends of two channel pieces, and the strap fastening one end of a brace.Each strap hinge is positioned to allow the gate to swing open all the way (180+45 degrees). The straps were too long, so each strap was cut shorter and a new beveled hole added.
Square-angle Bracing
To keep each rectangular panel 'square', that is, with square corners, heavy wires were installed diagonally, anchored by eye-screws, to pull opposite corners toward each other.Since each gate is supported only on the hinge side, only one diagonal wire was installed, to keep the outer edge from sagging.
The tension of the bracing wires will be more easily adjusted by using a tension adjuster like that shown here. Left- and right-handed threads enable turning of the joining part to change the tension without turning either end of the device.
Gate Latches
Each gate is held closed by a latch-bar, seen here at the top of the gate. Lifting the end of the latch bar releases the gate. The latch bars are made of the same material as the bracing bars.A piece of wedge material is added to the top of each gate, the wide side of the wedge toward the outside.
Monday, December 15, 2014
http://metro.co.uk/2014/12/13/seven-mind-scrambling-science-ideas-only-geniuses-can-understand-4985026/
The article said that "The world’s scientists don’t just sit around doing really hard maths for fun – they also believe some truly crazy ideas."
My comments on these seven ideas follow. but first, keep in mind that science does not explain everything; we must also deal with metaphysics, philosophy, and theology here. Science has been defined as the study of all that is material (mass-energy-space-time), so only materialists, those that ascribe to the metaphysical notion that everything is material (non-material things are imaginary) -- only materialists believe that science can explain everything.
In this modern era, we also study information just as intently, but information is not made of mass-energy-space-time -- mass and energy are only used in arbitrarily different ways for tranport of information through either space (communication) or time (storage). Information is observed only where life is observed. This frustrates the materialists, who resort to all kinds of stupidity trying to explain life. (For more on this, read my blogs such as http://jamesmclark.blogspot.com/2005/07/in-beginning-was-information.html,
http://jamesmclark.blogspot.com/2007/06/is-encoded-information-essential-part.html, http://jamesmclark.blogspot.com/2008/09/life-is-more-than-chemistry.html, and.http://jamesmclark.blogspot.com/2010/03/digital-control-of-life.html.) To define information theory as part of science, you either have to change the definition of 'material' or stop being a materialist.
1. Time goes slower on the Space Station
"This isn’t just theory – it’s actually measurable."
A proven fact. From working on GPS, I know that when we make and test the time-keeping system of a GPS satellite on the ground, we have to 'set the clock' a little faster on the ground so that after it is launched, it will agree with our global time-keeping system on the ground. The 'correction' is mostly to account for the speed of the satellite (a 12-hour orbit), but also to account for the decreased gravity (altitude).
2. We are almost certainly living in the Matrix
"British philosopher Nick Bostrom claims that we are probably living inside a Matrix-style simulation."
A conjecture. I think that if Nick Bostrom studied complexity theory, he would change his mind.
3. In a class of 25 children, two will probably share a birthday
"But it’s actually more likely than not that two will share a birthday – a chance of 57%."
Yes, the probabilty is closest to 50% for a class of 23; for 25, the probability goes up a little. As I recall, it is a difficult calculation requiring surprisingly high precision.
4. There is more than one universe
"There are billions, according to a theory which is accepted by ‘nearly all’ cosmologists."
A conjecture. This is based on the accepted fact that the universe that we observe is finite. Most people would think that this requires that the universe has an edge, or boundary. But topologists know that a 3D space can be folded on itself edgelessly, like the 2D surface of a sphere, for example. So, some far-away galaxy might be our local galaxy (the Milky Way) many, many years ago. This conjecture is scientifically unprovable, but many Christians assume that heaven is in another universe. (We really don't know.)
5. There are more than four dimensions
"...there are either dimensions too small for us to see, or that our 4D world exists on a ‘brane’ which floats in another, higher-dimensional world."
Only in subatomic physics. The extra dimensions 'fold up' within the tiny spaces of atoms.
6. No one knows what a computer is
"Computing professors worry about this stuff. Is an abacus a computer? Is a sundial?"
This is really just saying that there isn't yet a universally agreed definition of a computer, especially of very small ones. I once designed a computer with only one bit of internal memory and unlimited external memory, which I started to build but never finished. It would have been practically useless, taking a very long time to compute something very small.
7. The universe should not exist at all
"The universe may not have started with a Big Bang", the article says.
"Prof Mersini-Houghton’s calculations seem to prove that when a dying star collapses in on itself, it does not shrink down to become a ‘singularity’, ... what we know as a black hole.
Instead, the radiation that escapes from dying stars robs them of their mass, so they never have enough gravity to form black holes.
This creates a major problem. The ‘fuse’ that lit the Big Bang is supposed to have been a singularity – something which has now been proven not to exist."
I think this conundrum is a consequence of relying only on science. In other words, it results from an inherent limitation of science. It demonstrates a fundamental question that science alone cannot explain. All you can conclude is that something outside of science created the universe. If you add information theory to your thinking toolbox, you can conclude that 'that something' had an enormous amount of information, since we know that the material universe can destroy information but can never create it. And since information is observed only where life is observed, we can also conclude that 'that something' is living. It takes theology to go further than that, and the Bible to go in the right direction.
Monday, June 02, 2014
How to use the "WHAT IS NUMBER" T-shirt
Matrix of numbers 1 to 144 with rows and columns labelled
B
|
I
|
W
|
H
|
U
|
R
|
S
|
E
|
A
|
N
|
T
|
M
|
|
B
|
144
|
1
|
2
|
3
|
4
|
5
|
6
|
7
|
8
|
9
|
10
|
11
|
I
|
12
|
13
|
14
|
15
|
16
|
17
|
18
|
19
|
20
|
21
|
22
|
23
|
W
|
24
|
25
|
26
|
27
|
28
|
29
|
30
|
31
|
32
|
33
|
34
|
35
|
H
|
36
|
37
|
38
|
39
|
40
|
41
|
42
|
43
|
44
|
45
|
46
|
47
|
U
|
48
|
49
|
50
|
51
|
52
|
53
|
54
|
55
|
56
|
57
|
58
|
59
|
R
|
60
|
61
|
62
|
63
|
64
|
65
|
66
|
67
|
68
|
69
|
70
|
71
|
S
|
72
|
73
|
74
|
75
|
76
|
77
|
78
|
79
|
80
|
81
|
82
|
83
|
E
|
84
|
85
|
86
|
87
|
88
|
89
|
90
|
91
|
92
|
93
|
94
|
95
|
A
|
96
|
97
|
98
|
99
|
100
|
101
|
102
|
103
|
104
|
105
|
106
|
107
|
N
|
108
|
109
|
110
|
111
|
112
|
113
|
114
|
115
|
116
|
117
|
118
|
119
|
T
|
120
|
121
|
122
|
123
|
124
|
125
|
126
|
127
|
128
|
129
|
130
|
131
|
M
|
132
|
133
|
134
|
135
|
136
|
137
|
138
|
139
|
140
|
141
|
142
|
143
|
Cipher and mnemonics:
W
|
2
|
tWo, first
spelled number with W
|
H
|
3
|
tHree, first
spelled number with H
|
A
|
8
|
sounds like Ate
|
T
|
10
|
Ten, fourth
spelled number with T
|
I
|
1
|
I looks like 1
|
S
|
6
|
Six, first
spelled number with S
|
N
|
9
|
NiNe, first
spelled number with two N's
|
U
|
4
|
foUr, first
spelled number with U
|
M
|
11
|
eleven –
Melvin (similar sound)
|
B
|
0
|
B00, surprise,
O looks like 0
|
E
|
7
|
sEvEn, first
spelled number with two separate E's
|
R
|
5
|
fiveR, slang
for 5-dollar bill
|
Result = 12 * Fr + Bk
You can calculate the 12 * Fr part while the back number is being found.
The Reverse Trick
You can do the magic trick in reverse. That is, given 54, for example, you can determine where it is found without looking. You divide 54 by 12, getting the quotient 4 and remainder 6. Using the cipher, you convert the quotient 4 to U, the position on the front of the shirt, and you convert the remainder 6 to S, the position on the back of the shirt.Another Trick
For any letter, there is a number that appears under that letter on both the front and the back of the T-shirt. So you can ask a volunteer to choose a letter, and then you choose a number that appears under that letter on both the front and the back. To do this, it will help to be familiar with the multiples of 13. (Most people are not, and as a result, think that 91 is a prime number.)Given a letter, use the cipher to convert the letter to a number, then multiply the number by 13. For example, suppose the letter is E. According to the cipher, the corresponding number is 7. 7 times 13 is 91, so you declare that 91 is found in box E on both the front and the back of the T-shirt.
The equivalence of 0 and 144 applies to all tricks.