Fox and Hounds

Only the dark squares are used.
The four hounds are initially placed on the dark squares at one edge of the board; the fox is placed on any dark square on the opposite edge.
The objective of the fox is to cross from one side of the board to the other, arriving at any one of the hounds original squares; the hounds objective is to prevent it from doing so.
The hounds move diagonally forward one square.
The fox moves diagonally forward or backward one square.
The play alternates with the fox moving first.
The player controlling the hounds moves only one of them per turn.
The fox is trapped when a hound occupies all four of its potential move squares.
Alternatively, two hounds may trap the fox against an edge of the board (other than their original home-row).
There is even one corner where a single hound may do the trapping.