Stanley Collins came up with a distinctive variant on the standard Ace Assembly when he published a version in which each of the first three Aces is shown face up in its pile and then disappeared very cleanly from it. All four Aces are then shown to be in the fourth pile; see “The Stanley Collins Four Ace Experiment in The Magazine of Magic, Vol. 1 No. 1, Oct. 1914, p. 8.

Collins's idea of stressing the vanish of each of the three Aces would become a component in Dai Vernon's “Slow-Motion Four Aces”.

• Category in Denis Behr's "Conjuring Archive"