Having finished with triangular faces, let's move on to square faces. Placing three squares around a vertex gives something that looks like the ceiling and two walls of a square room. If we create another one of these, we can turn it so that is looks like two walls and a floor of a square room. Joining the edges of these two pieces creates the familiar cube, the regular solid with three square faces at every vertex.
Since four squares around a single vertex lies flat in the plane,
there is nothing more we can do with squares.