_CELLULAR AUTOMATA FOR SOLVING MAZES_
by Basem A. Nayfeh

[EXAMPLE ONE]

#define FALSE 0
#define TRUE  1
#define FREE  0
#define WALL  1

  do {
    steadystate = TRUE;
    /* scan the entire CA */
    for (x=1;x<Xsize-1;x++) {
      for (y=1;y<Ysize-1;y++) {
        if (cell[x][y] == FREE) {
          /* addition can be used here to determine if */
          /* a cell is  surrounded by 3 or more walls  */
          if ((cell[x+1][y] + cell[x-1][y]

             + cell[x][y+1] + cell[x][y-1]) >= 3) {
            cell[x][y] = WALL;
            steadystate = FALSE;
          }
        }
      }
    }
  /* keep scanning the CA until */
  /* a steady state condition is reached       */
  } while(!steadystate);

  /* the cell array now contains the correct solution(s) */
  /* denoted by the remaining free cells                 */

  /* no solution if all cells are now wall cells         */