And even though polygon themselves can't be 3D shapes, you can use polygon to make 3D shapes. Like a box , for example the box is not a polygon. But each of it's flat sides is a polygon. Alright then , we have aspecific difinition of a polygon. A polygon is a multi-sided shape that has sides,vertices and angles. A polygon is a closed shape, and polygon is a 2-dimensional , or flat shape . And now that you know that, it's time to play "polygon or not a polygon" now here's you host:me!