| 摘要 |
A tennis-ball is made by covering a spherical core with twelve substantially identical pentagonally-shaped pieces of a cover material. Before the pentagonally-shaped pieces are attached to the core, they are covered on their outermost surface by a removable layer of adhesive-impermeable barrier material (e.g. tissue paper). The barrier material restrains the movement of the pentagonally-shaped pieces when applied to the spherical core, so that a narrow uniform seam is obtained. When all twelve cover pieces are correctly positioned on the core, the barrier material is removed and the assembly subjected to a random rolling action to "finish" the ball. |
