tileid = tile_add(tlSandBlocks, (image_index * 16), 0, 16, 16, x, y, -100)
if sandcrn0
    tilesandcrn0 = tile_add(tlSandCorners, 0, 0, 16, 16, x, y, -101)
if sandcrn1
    tilesandcrn1 = tile_add(tlSandCorners, 16, 0, 16, 16, x, y, -101)
if sandcrn2
    tilesandcrn2 = tile_add(tlSandCorners, 32, 0, 16, 16, x, y, -101)
if sandcrn3
    tilesandcrn3 = tile_add(tlSandCorners, 48, 0, 16, 16, x, y, -101)