Suppose we are given an environment consisting of axis-parallel and diagonal line segments with integer endpoints, each of which may be reflective or non-reflective, with integer endpoints, and an initial position for a light ray passing through points of the integer grid. Then in time polynomial in the number of segments and in the number of bits needed to specify the coordinates of the input, we can determine the eventual fate of the reflected ray.

翻译：假设我们被赋予由轴平行线和对角线段组成的环境,其中含有整端点,每个端点可以是反向的,也可以是非反向的,有整端点,以及光线穿过整格网点的初始位置。 然后,在时间上,可以确定反射线的最终归宿。 在时间上,分点数和指定输入坐标所需的位数的多位数,我们可以确定反射线的最终归宿。