If you go into this elevator, you be will surprised for least first few seconds. There is a sign at the entrance about the work in progress in the elevator. Actually, the floor of this elevator has been painted with an illusion to make people feel there is no floor. Maybe you can ask your friends to close their eyes & make them go into this elevator & ask them to open their eyes to look on the floor.
Coke Can Tuxedo
Design Interior: Optical Illusions In Reality