Step 1: Preparation
Place the four aces on the top of the pile before performing the trick.
Step 2: Trick
Tell the spectator to cut the pile into four. Now mix up all the piles but the one with aces on.
Step 3: The End
Tell the spectator that to have mixed up the piles( remember that when mixing piles put the aces on the top of each pile )
Turn over the top card, they are all aces