Why are meatballs round?

Answer 1

Most people just find it easiest to roll them between their hands which is what makes them round. The ball shape also makes it easier to roll around in a pan to brown them.

Meatballs don't need to be round. You can make them any shape you want. Other shapes will just take more trouble to shape and will have to be manually turned in the pan while browning. Make some in the shape of mini Hot Dogs or try rolling out the meat mixture flat and making shapes with a small cookie cutter or canape cutter or cut triangles, squares and rectangles.