Drawing Positions

The knight, unlike the other pieces, cannot "lose" a move in order to give the move to the opponent -- the knight can't triangulate.
The key to drawing the following position is that the king needs to stay on the same colored square as the knight. In other words, if the knight is on a dark square, the king wants to move to a dark square; and if the knight is on a light square, the king wants to move to a light square.

In knight and pawn vs lone king positions, a rook's pawn on the 7th is a draw.

A common fortress.