xmin=gridMax;
ymin=gridMax;
for( x = 0; x < gridMax; x++ ){
  for( y = 0; y < gridMax; y++ ){
    if(grid[x,y].RoomHere == yes) {
      if(x<xmin) xmin=x;
      if(y<ymin) ymin=y;
    }
  }
}