water caltrop (esp. Trapa japonica); water chestnut; caltrop (weapon)
rhombus; rhomb; lozenge; diamond (shape)
stitching chisel; pricking iron; multi-prong punch for leather-craft
white diamond shape; white diamond signal shape (marine safety context)
groundhopper (esp. species Tetrix japonica)
bean goose (Anser fabalis)