The term BALL MATERIAL can refer to four different materials: SNOW, matzo, nerf, and YARN. SNOW is a type of frozen precipitation that falls from the sky in cold climates. Matzo is a type of unleavened bread traditionally eaten during Passover. Nerf is a brand of soft foam toys that are popular with children. YARN is a type of thread made from natural or synthetic fibers that is used for knitting and crocheting.