When Howard is carrying 10 ice creams outside the shop, the ice cream is white, floppy-looking, and melting, like real ice cream. Once inside the hairdresser, the ice cream is yellow and in neat cuboids.
When Martin's bingo machine starts spewing ping-pong balls at a vast rate, it is obvious that they are emerging from a hidden reservoir of balls in the base rather than the transparent tank where they are supposed to be coming from, as that tank contains only a small and unchanging number of balls which remain completely stationary throughout.