利用撞球研究遍历理论，在一个正方形内研究撞球，利用展开的方法研究起轨迹，（附带加入TILING的方法构造障碍物），研究障碍物无限的情况下，遍历理论-Ergodic theory study of the use of pool, in a square within the study pool, using the method started from track, (with TILING is constructed by adding obstacles) to study the infinite barrier case, the ergodic theory