Image Credit:
Here's a trick to play on someone, take one elevator and paint the bottom of it with an anamorphic illusion to make it look as though it has no floor. This fellow doesn't want to stand on it and I don't blame him, the 'hole' looks so real its hard to tell that its only an illusion. Would you stand on there ?
Simple , don't look the floor and only look through the windows. Ha ha