Triangular and square watermelons were invented by Japanese graphic designer TomoyukiOno. The production method is to put a mold on the watermelon during the growth process, so that the watermelon can grow into the desired shape.
1978, graphic designer TomoyukiOno invented and exhibited triangular and square watermelons in a gallery in Ginza, Tokyo. In addition, she applied for and obtained a patent in the United States. This kind of watermelon was originally invented for the convenience of cutting in a small refrigerator (it won't roll). Later, this kind of watermelon became more and more popular in Japan.