TILE_FLAG_MM_UNSEEN = 0x00000000,
    TILE_FLAG_UNSEEN    = 0x00001000,
    TILE_FLAG_CURSOR0   = 0x00002000,

    TILE_FLAG_MM_UNSEEN = 0x00001000,
    TILE_FLAG_UNSEEN    = 0x00002000,

        // FIX ME: add real neutral marker!
        tcache_overlay(tc_img, ix, TILE_NEW_STAIR, TREGION_0_NORMAL, &c, NULL);
        status_shift += 10;

        tcache_overlay(tc_img, ix, TILE_NEUTRAL, TREGION_0_NORMAL, &c, NULL);
        status_shift += 8;

neutral NEUTRAL