Error in magic chapter in Visual Explanations?

This has nothing to do with information design, but I thought I’d
point out what appears to be an error in your description of the
‘Downs Eureka Pass’ sleight of hand.

Briefly (for those who don’t have the book): a magician with his
right hand makes a coin seem to vanish while in fact concealing
it behind his fingers. The left hand then openly transfers a
second coin to the right, surreptitiously taking the first, hidden
one in the process. The right hand then ‘vanishes’ the second
coin in the same manner as the first, and the cycle can repeat.

ET writes: “Since the left hand must hide an increasing
accumulation of potentially clinking coins, the repeated cycles
grow more difficult.”

Surely, only two coins are required, and neither hand ever holds
more than one. The ‘vanished’ one becomes, moments later, the
next ‘new’ one apparently drawn from a nonexistent supply in a
pocket or other container.

The ‘reverse’ of this effect is to make coins ‘appear’ in the right
hand by essentially the same technique. The left hand in taking
the coin loads a second one into the concealed position, so
another coin can appear in the right moments later. Usually the
magician will with his left hand pretend to drop the just-
appeared coin into a metallic pail, which emits a nice loud ‘clink’
to signal that the coin has hit the bottom. In fact, there’s a device
hidden in the pail which creates a false noise, as the magician
conceals the first coin again in his left hand, for transport back to
the right as the cycle repeats. The audience doesn’t actually see
the coins falling into the pail (“Hey, why doesn’t he use a glass
bowl?”) but their ears get the message, and believe.

We now return you to your regularly scheduled topics…