A program to solve the Pentomino problem by the recursive use of macros

Just as a domino is a platte figure formed of two contiguous equal squares, a pentomino is a plane figure formed of five contiguous equal squares. A fixed size for the elemental squares being assumed, there are 112 different pentominos, different meaning noneongruent. These are each identified by a number front 1 to 12 (see Figure 1). Ihe pentonfino problem is the problem of fitting the 12 pentomittos without overlapping into a plane area (the box) formed of 60 elelnetttal squares. The box may be rectangular (3 X 20, 4 X 16, 5 X 12 or 6 X 10) but is not necessarily so. In the program, the box is viewed as a portion of a large arena, 16 X 32 squares; these squares arc numbered from i: 1 to 512, 1 to 16 proceeding from left to right across the ~ first row, 17 to 32 across the second, etc. Each square