Image Item No. Description  49308  Brick, Round 3 x 3 x 1 1/3 Dome Top - Open Stud Catalog: Parts: Brick, Round  73111  Brick, Round 3 x 3 x 2 with Recessed Center and Axle Hole Catalog: Parts: Brick, Round  79850  Brick, Round 4 x 4 Dome Top with 2 x 2 Recessed Center Catalog: Parts: Brick, Round