How many rotund heroes can you think of? Okay, it doesn't actually matter how many you can think of, the only chubby hero that matters for the sake of this article is the one and only Mario, and Shigeru Miyamoto explains why the plumber looked the way he did when he first appeared on our screens.
The reason Mario is a plump shape is because gaming devices at that time could only read collisions between square boxes, not because I wanted to make him cute. His design turned out like that because I adjusted for the capabilities of the gaming device of the day. For example, resolution was low, so I made his face big. But today's game consoles can handle collisions with round or irregular shapes.
The collisions are how in-game solid objects know when they come into contact with other objects. We wonder if Mario's debut was today, would he look similar or totally different? Maybe Mario would be slimmer like Luigi and Luigi would be the token fat brother?