Why is a baseball field in the shape of a diamond?

Diamond Baseball Field

If you look at it, it's really a square. It only looks like a diamond if you look at from directly behind home plate (or one of the other bases.)

If you want four bases all the same distance apart, that forces it to be a rhombus. But it would be weird if 3rd base was closer to 1st than 2nd is to home. So a square is the only logical choice, the four-sided regular polygon.

If we went to five-Baseball, then there might be some other options, but I bet it would end up a regular pentagon.

It also is so the distance between each base is equal.