Some thing that is a 4-sided polygon or triangle

4 sided polygon:
baking pan, tile, hanging clock, biscuit, watch, poster, blackboard, calculator, lap-top computer, book, cutting board, wallet, paper, picture frame, door, photograph, playing cards, dish plate, adhesive bandages, electronic scale, table top, pendants,

triangle:
tile, hanging clock, spear head, arrow head, shark's tooth, watch, poster, table top, pendants,

2008-06-17 22:38:18 補充：
4 sided polygon: mirror
triangle: mirror

textbk, clock, brick, etc.