func (self *Game) Roll(pins int) {
	self.rolls[self.current] = pins
	self.current++
}
Roll rolls the ball and knocks down the number of pins specified by pins.
package examples
type Game struct {
	rolls   []int
	current int
}
func NewGame() *Game {
	game := new(Game)
	game.rolls = make([]int, maxThrowsPerGame)
	return game
}