C
for durability. The blocks in 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).
Figure C shows one of the best designs,
with each block made of two wooden slabs
glued together, and the ribbon ends secured
between them.
As you rotate the top block, you keep it
at a constant height. The visual impression
is that the block tumbles all the way to the
bottom, especially if the blocks are the same
color and only one color of ribbon is used.
In action, each block just rotates 180° and
doesn’t fall at all.
The Tumbling Rings
The first description I saw of this illusion was
in a 19th-century book of magic tricks for
entertaining. It later appeared in Scientific
American, in Martin Gardner’s “Mathematical
Games” column in the 1950s. Formerly called
“Afghan rings,” these assembled chains may
be purchased at magic shops.
Photograph by Donald Simanek (D)
For the tumbling rings illusion, an even
number of rings is interlinked as shown in
Figures D and E. I used split key rings, which
can be found in several sizes in craft or hardware shops.
If you hold the top ring (ring A), you can
test the two rings just below by trying to lift
them. Ring B can be lifted so it will cause the
half-chain below to lift with it. Ring C lifts the
whole chain — ignore it.
Hang onto ring B and let go of ring A. You
D ABC
F
E
; Fig. E: The two inter-
linked chains of rings. Ring
B is about to become the
top ring.
; Fig. F: The tumbling
rings in action, with the
“falling” ring halfway down.
may be rewarded by a smooth “falling” action,
which appears to onlookers like the top ring
fell all the way to the bottom.
Actually nothing falls. The other side of the
chain simply untwists, giving an illusion of
falling. If this doesn’t happen, you’ve grasped
ring B on the wrong side (try grabbing the
other side), and thus dropped A in the wrong
direction (try the opposite direction). If the
tumbling illusion “hangs up” on the way down,
you’ve interlinked some rings incorrectly.
Sometimes it helps the illusion to release
the top ring with a bit of rotational flourish,
giving it initial 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 falling.
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