Abstract: A ball includes a ball body having a spherical surface, and at least one projection extending from the surface of the ball body. The projection extends in such a manner that the projection forcibly separates a laminar boundary layer generated on the surface of the ball body, and transitions the laminar boundary layer to a turbulent boundary layer.

Abstract: A compact portable athletic data display apparatus, comprising a generally rectangular flat display section 3 which is rotatably connected at the lower end thereof with a generally rectangular flat control section 2 by means of hinges, so that the display section 3 may be held at upright position to display the data when it is used but folded onto the control section otherwise. In operation, an operator stands up the display section 3 at the upright position, enter data to be displayed on the display section using data input keys. A monitor may be provided on the control section so that he may check on the monitor the data he has entered for display.