Monotone polygon

A monotone polygon is a special kind of shape that only goes up and down, or left and right. Imagine if you had a shape made with straight lines, like a square or a triangle. A monotone polygon would be if all the lines were going in the same direction, either up and down or left and right.

It's like walking up and down a staircase. You go up one step and then down the next step, and you keep doing that until you reach the top or bottom. A monotone polygon is like a shape that you could walk up and down or left and right, but you wouldn't have to turn or go in any other direction. It just keeps going in the same direction until you reach the end.