### Instruction: Classify each of the following as either round or square shape: wheel, paper napkin, building block, ring, coin, ball, grid, bread, bubble, dice, hula hoop, window, stamp, earth, crossword, tambourine, bagel, keyboard key, cube, letter O.
### Response: Objects that have circular (round) shape include: bagel, ball, bubble, coin, earth, hula hoop, letter O, ring, tambourine, wheel.
Objects that have square shape include: bread, building blocks, crossword, cube, dice, grid, keyboard key, paper napkin, stamp, window.