#include <stdio.h>

#define W 60
#define H 40

typedef unsigned char Board[W*H/8];
static Board board;

static _Bool
get(Board *b, unsigned x, unsigned y) {
   x %= W; y %= H;
   unsigned idx = x + y * W;
   return (*b)[idx/8] & (1 << (idx % 8));
}

static void
set(Board *b, unsigned x, unsigned y, _Bool set) {
   x %= W; y %= H;
   unsigned idx = x + y * W;
   (*b)[idx/8] &= ~(1 << (idx % 8));
   if (set)
      (*b)[idx/8] |= (1 << (idx % 8));
}

static void
next(Board *b) {
   Board temp;
   memcpy(temp, &**b, sizeof temp);
   for (int y = 0; y < H; ++y)
      for (int x = 0; x < W; ++x) {
         #define C(ox, oy) get(&temp, x + ox, y + oy)
         int n = C(-1,-1) + C(0,-1) + C(1,-1)
               + C(-1, 0)      +      C(1, 0)
               + C(-1, 1) + C(0, 1) + C(1, 1);

         set(b, x, y, 0);
         if (get(&temp, x, y))
            set(b, x, y, n == 3);
         else if (n == 2)
            set(b, x, y, 1);
         else if (n == 3)
            set(b, x, y, 1);
      }
}

static
void draw(Board *b) {
   printf("\x1B[H\n");
   printf("\n");
   for (int y = 0; y < H; ++y) {
      printf(" ");
      for (int x = 0; x < W; ++x) {
         if (get(b, x, y)) {
            printf("W");
         } else {
            printf(" ");
         }
      }
      printf(" \n");
   }
}


static void
init(Board *b) {
   int time(void *);
   unsigned rnd = time(0);
   for (int y = 0; y < H; ++y) {
      for (int x = 0; x < W; ++x) {
         set(b, x, y, (_Bool)((rnd >> 31) & 1));
         rnd = (rnd * 134775813) + 1;
      }
   }
}

void usleep(unsigned);
int main () {
   init(&board);
   for (;;) {
      draw(&board);
      usleep(100);
      next(&board);
   }
}