A prism consists of two copies of any chosen regular polygon (one becoming the top face, and one becoming the bottom face), connected with squares along the sides. By spacing the two polygons at the proper distance, the sides consist of squares rather than just rectangles. At each vertex, two squares and one of the polygons meet. For example, based on a 7-sided heptagon, is the heptagonal prism (4,4,7).
An antiprism also consists of two copies of any chosen regular polygon, but one is given a slight twist relative to the other, and they are connected with a band of alternately up and down pointing triangles. By spacing the two polygons at the proper distance, all the triangles become equilateral. At each vertex, three triangles and one of the chosen polygon meet. Example: heptagonal antiprism. (3,3,3,7).
I have included models of prisms and antiprisms ranging from three sides up to ten sides in this list of prisms and antiprisms. You can generate prisms and antiprisms of any size, on the fly, with the prism maker.
Kepler was the first to discuss antiprisms,
and recognize the connection between prisms and the Archimedean solids.