The kinds of prisms we look at here are more correctly known as right prisms. A prism is a solid shape in which the top and bottom faces lie on top of each other so that the polygons connecting their sides are rectangles. An unusual one is shown below. If the top and bottom faces are rectangles then the prism is known as a cuboid.

Euler discovered a relationship between the faces, vertices and edges of these solids: vertices + faces = edges + 2.

JavaView: Help with diagrams
In every diagram you can click and drag the left mouse button to rotate each spae. Press your right mouse button to select different interaction modes from a popup menu, or use keyboard keys to temporarily switch between different modes (just keep a button pressed to switch mode temporarily). Some essential modes are: