When in football, tennis or other similar game ball leaves the field of play, the game is stopped, the ball is returned back and one of the players, observing certain rules, it again enters the game. On the ice, the situation is different. The field is framed rim, solid wooden barrier that throws the puck hit him on the back, and the game continues without interruption. Hockey players subconsciously seize the laws of reflection. They use the rule "the angle of incidence equals the angle of reflection" to their opponent. As long as the puck hits the straight sections of a side, everything is very simple. But quite a different situation in the field corners. There's a side has a curved shape. When the puck deflects off of him in such places, then flying, gliding on the ice, in the most unexpected ways. If you are not interested in hockey, you still read this section. What is true for the angles of ice Fields, valid for the shaving mirrors, mirror reflectors in flashlights, speaker. In many families, there are small-format games to test agility. Their essence is to drive into a crescent field enclosed by glass, one or more balls. Balls encounter playing field wall, typically having a rounded shape. Where did they bounce?