No. LX.—THE OPEN DOOR
The prisoner who is placed in the cell marked A, and is promised his liberty if he can reach the door at X by passing through all the cells, entering each once only, gains his freedom by passing from A to the cell below, and thence returning to A, and leaving it again by the other door; his further course then is quite simple.
No. LXII.—LEAP FROG
Move 9 to 13, 3 to 9, 7 to 3, 22 to 7, 18 to 22, 24 to 18, 9 to 24, 13 to 9, 7 to 13, 3 to 7, 18 to 3, 22 to 18.