Toys, Tricks and Teasers.

by Donald Simanek.

Fig. 1. Jacob's ladder toy.

Kinetic Illusion Toys.

Visual illusions come in many forms. The commonest are flat pictures, cleverly made so that they seem to show something that is impossible in reality. A smaller category is the kinetic illusion, an illusion caused by motion of real objects. Every time we watch television or the cinema, even in 3d, we are seeing an illusion of depth and motion produced by a series of still, flat pictures. Old western movies often displayed a stroboscopic illusion when the spokes of a moving wagon wheel seemed to be rotating the wrong way relative to the motion of the wagon.

Jacob's Ladder.

Motion pictures arose from illusion toys, but that's fodder for a separate article. Today I consider just two kinetic illusion toys, one well-known, one not so well-known. Both give illusions of something continuously falling, but it doesn't fall.

The folk toy called "Jacob's ladder" is also known as the "magic tablets", the "Chinese blocks" or the "klick-klack" toy. We don't know exactly when or where it originated. It is a simple toy consisting of blocks of wood strung together with ribbons. When suspended from one end, and the top block turned over, a block appears to slowly fall to the bottom, flip-flopping with a nice clattering sound.

The first documented description of this toy is from Scientific American in 1889. Not many toys have generated a historical mythology as this one has. Some say it was found in King Tut's Tomb. But the contents of that tomb were carefully inventoried when it was discovered, and no mention is made finding anything like this toy. The name "Jacob's ladder" may refer to the biblical description of a ladder one could climb to Heaven, mentioned in Genesis 28:12. Some say it was one of the few toys some Christian households allowed their children to play with on Sundays. This seems unlikely, for the toy doesn't look anything like a ladder, and it gives the illusion of a block falling down, not climbing up to Heaven. It would truly be a miracle if it fell up. There is a widely believed story that an angel named Lucifer was kicked out of heaven and fell way down to found the kingdom of Hell, but that's a misreading of the Bible.

Fig. 2. Jacob's ladder in action.

Minor variations of this toy have been frequently patented. US patents include 2,310,711 (1943), 2,809,467 (1957), 3,530,614 (1970), 4,095,366 (1978), 4,183,166, and just this year patent application 20,100,227,529. This short listing is only a sample of patents by folks who have sought profit from this toy. E. S. Savage's 1943 patent 2,310,711 shows how a simple idea can stimulate clever extensions of that idea. Not bad for a toy alleged to have been played with by King Tut.

Commercial versions of Jacob's ladder consist of colored blocks strung together with colored ribbons. Those with blocks of mixed colors, in my opinion, compromise the illusion of a falling block. In the 1940s when I was a child, these toys were sold with a round indentation in one block with a penny nested in it, so you could perform a little trick to make the penny seem to vanish. Its block just flipped when the block stack was unfolded, so the side with the penny was on the bottom side, secured by the center ribbon. Those were the days when, for a kid, a penny was worth having. A folded dollar bill works even better.

Fig. 3 shows how to string the ribbons to construct one of these toys. The ribbons can be narrow or wide, but I suggest good quality strong, non-stretching cloth ribbons for durability. Some commercial sets have rounded edges, which reduces ribbon wear and gives the smoothest operation. If squared-edge blocks are used the ribbons can be secured with small tacks or glue (only at the ends of each block). Fig. 4 shows one of the best designs, with each block made of two wooden slabs glued together, and the ribbon ends secured between them. Use four ribbons if you like.

In action, each block just rotates 180° It does not fall at all. As you rotate the top block you are unconsciously keeping it at a constant height. The visual impression is that a block tumbles all the way to the bottom, especially if you use blocks of the same color and only one color of ribbon.

Fig. 3. How the ribbons ends are secured between the two halves of each block.

The tumbling rings illusion.

Fig. 4. The tumbling rings.
Use this as a construction guide.

The first description I saw of this was in a 19th century book of magic tricks for entertaining. It later appeared in the Scientific American, in Martin Gardner's "Mathematical Games" column, in the 1950s, when I was in high school. An even number of rings are interlinked as shown Fig. 4 and 5. I first used split key rings, which can be found in several sizes in craft or hardware shops.

When the chain is assembled, hold the top ring and test the chain by trying to slightly lift one of the two rings below it. (This requires two hands.) One of the rings, when lifted, will cause half of the links below to lift with it. Hang onto that one and release the top one. You may be rewarded by a smooth "falling" action which looks to the audience as if the top ring tumbled all the way to the bottom. Actually nothing falls. One side of the chain untwists, giving an illusion of falling. If this doesn't happen, you have grasped the wrong part of the second ring. Try grasping the other side of it. If the tumbling action "hangs up" on the way down, you may have interlinked some rings incorrectly. Sometimes it helps the illusion to release the top ring with a bit of rotational flourish to give it the correct angular momentum.

Once you get the hang of it you can keep a tumbling action going by transferring your hold from the top ring to the next after each fall, timing your action to the period of fall. At any step, there are four places you can grasp a ring below; three of them are wrong. Suppose grasping the left ring nearest to you works. Then the next time grasp the right ring at the point farthest from you and keep alternating this action. In Fig. 4, when the chain is held at ring A, the place to grab and lift is the near side of ring B. Then release ring A. Ring C is the wrong one. Fig. 6 shows ring B being lifted with the middle finger.

Martin's description inspired me to make one for myself, and I hope you do, too, for a verbal description can't convey the hypnotic fascination of watching it in action. I went to a key-making shop to get the rings, 20 of them. The proprietor said "You must have a lot of keys." So I explained what I intended to do with them. He hadn't heard of anything so daft, but he must have sensed my enthusiasm for the project and he ended up giving me the rings at a substantial discount. Those were different times.

Fig. 5. Paper model of the tumbling rings.
The colors help to show how the rings must be linked.

The actual assembled chain does not lie flat, which makes it difficult to illustrate with a drawing. In fact, some previously published drawings show improper linkage, and could never work. Use Fig. 4 and 5 as a guide. Notice that pairs of rings naturally lie side by side when suspended as shown in Fig. 4. When you assemble the length you want, or are about to run out of rings, just link a final ring through the bottom two and the chain is finished. The chain will have topological symmetry top to bottom. It will look the same and operate the same whichever end you suspend it from.

A chain of 2 inch key rings is easily carried in a pocket. I have made larger sets using plastic macramé rings from craft stores, the kind that can be opened at a locking socket, linked and then re-locked. I have also made a set using craft-store steel rings. Half of the rings must be sawed open at the weld point with a hack saw. Assemble the ring chain then weld the breaks closed. File off irregularities from the welds. Five-inch rings are about the limit of size for good performance. Larger sets fall more slowly, and the illusion isn't as effective.

Fig. 6. The chain assembled from key rings. Fig. 7. Demonstrating that it is two interlinked chains. Fig. 8. The falling ring illusion caught by flash.

Assembled chains with metal rings may be purchased at magic shops. They used to be called the "Afghan Rings".

In action it appears that the top ring is released and then cascades all the way to the bottom. But in fact, you are just exchanging the top ring with the next one down the chain and half of the chain twists 180°, starting at the top. You could easily confirm this by taping a marker on the top ring—if you had any doubts.

A nice touch when showing this to an audience is to finish by inverting the chain and then demonstrating that it works just as well in reverse. "Explain" that you are restoring the chain to its original condition, putting the rings "back where they belong" and thereby restoring the order and harmony of the universe.

I have never known anyone who could assemble one of these after simply observing it in action. Even with the instructions given above, most people struggle to link the rings correctly.


1. Scientific American, October 12, 1889, page 227.

2. Lanners, Edi. Secrets of 123 Old-Time Science Tricks & Experiments. TAB Books, 1981. Original by Verlag C. J. Bucher, Lucerne and Frankfurt, 1976. First English Language Edition by Paddington Press U.K. Ltd., 1978. Translation of Kolumbus-Eier, based on a larger collection entitled Columbus' Egg, first issued by the editors of Der Gute Kamerad in, two volumes, 1890.

3. The vanishing coins trick can be found at

{End of MAKE article.}

A vanishing trick with Jacob's Ladder.

Open the stacked blocks at the middle so you now have two stacks of 3 blocks side by side on the table, the bottom blocks of the stacks attached to each other, the top two blocks free. Open this by grasping the top two blocks where they touch and swinging them up and outward. Place a small coin on each of the exposed blocks below these. Close the top two blocks, covering the coins, and say your magic words. Now grasp the outer ends of the top two blocks and pull them outward so the string of blocks unfolds completely. The coins are nowhere to be seen. Hold the string of blocks horizontally, just above the table, so people won't suppose anything is hiding on the table under it. Now close the string of blocks back into two stacks, as it was before. To make the coins reappear, say those magic words backwards, then open the top two blocks as you did the first time, by lifting them up and outward at the center, where they touched each other. Where were the coins hiding? You could say "In the fourth dimension", but that would be lying. But magicians lie all the time. When you unfolded the entire string of blocks the coins were out of sight on the bottom of their blocks, held in place by the center ribbon. The ribbon just switched blocks, securing the coins, and the blocks flipped over.

Two stacks of three.
Swing the top two blocks
up and outward.
Place the coins on
the exposed blocks.
Fold the end blocks
back over the coins.
Grasp the outer edges
and pull outward.
The extended blocks are held above the table.
The coins are now on the bottom of the blocks,
held in place by the ribbons.

A little verbal deception can be used. Point out that you put the dime on the blue ribbon and the penny between the red ribbons. Then when you spread out the blocks, point out that the center two blocks still have the blue ribbon on the left and the red ribbon block on the right, but there are no coins to be seen. Most people will not notice that the blocks on which the coins were initially placed were not on the center two blocks, but were in the stack just above the center ones.

{If this is used in the published article, it would require at least these five pictures.}

{Note: All of the picture files above are larger in pixel count than they appear on this web page. All are by Donald Simanek.}