The boxes you see are ubiquitous on film sets. They are sturdy, have handles, and are used for temporary propping up of cameras, lights and people. I use it to sit on, to stand on, to put equipment on, to prop up tables. They come in this size, which is called the Full Apple, half this size is called the Half Apple, next is the Quarter Apple and, finally, the Pancake which is one-eighth size. The boxes are similar in size to the packing crates that were used to ship apples (I am guessing here).
Let me know if you have any innovative uses for your (real or imaginary) apple box!