case DNGN_SECRET_DOOR:
    {
        // If we have neighbouring walls, try to look like them.
        // Arguably we should go by our own colour, but well...
        for ( int dx = -1; dx <= 1; ++dx )
            for ( int dy = -1; dy <= 1; ++dy )
            {
                const dungeon_feature_type neighbour = grd[mx+dx][my+dy];
                if ( grid_is_wall(neighbour) )
                    return feature_description(neighbour, NUM_TRAPS,
                                               dtype, add_stop);
            }
        return (feature_description(grid, NUM_TRAPS, dtype, add_stop));
    }