Don't assume something is impossible just because it has never been done. Like the case of the Japanese watermelon,  just because it has always been round, doesn't mean it always has to be.

"Japanese grocery stores had a problem. They are much smaller than their US counterparts and therefore don't have room to waste. Watermelons, big and round, wasted a lot of space." 

Then, some Japanese farmers came up with a solution. They invented the square watermelon, by thinking outside the box — so to speak.

It turned out that all they needed to do was to place them in a square box when while are growing and the watermelon will take on the shape of the box.

"This made the grocery stores happy and had the added benefit that it was much easier and cost effective to ship the watermelons. Consumers also loved them because they took less space in their tiny refrigerators."

(READ more at Functional Medicine University) – Thanks to Sun Star for the link!