Copyright Richard Appel, Inc., NY, 1943.
(2.5"x2.5"x1" cardboard box, 2.4" square board, and eight 13/16" wood cubes;
Described on pages 135-136 of the
which dates the puzzle)
Start with the cubes placed on the board according to their color,
and then move the purple cube in the upper left corner to the lower right corner
in such a way that pieces of the same color never touch each other along a side.
The two purple blocks may not touch,
but are different shades of purple allow one to keep track of which is the one that started in the upper left.
Includes a 24 move solution;
Hordern presents a minimal 22 move solution:
G Y O Y G P Y O P G O G O Y G P Y O P G Y P