The balls are made of many substances like wood, metal, rubbery tree sap, and rock. They must not have a circumference of more than 27 inches, and they must not weigh more than 16 lbs. The object of the game is to knock down the ten pins with the ball. A game consists of ten frames, or squares into which the score is written. If this happens, he rolls only once.
Every bowler hopes for a strike with the first delivery on each frame.
The score increases quickly if this happens. If the bowler does not get a strike the next best is a spare, which is knocking down all the pins on two deliveries. A strike on the first delivery gives the bowler ten points, plus all the pins dropped on the next two throws. A spare in the second delivery gives the bowler ten points plus all the pins he gets on the first delivery of the next frame. Failure to strike or spare in a frame means that the bowler counts only the number of pins dropped.