In this practice, students read the source code of training
programs based on Computer Graphics Animation
(Named WinTK) and challenge to modify or extend these
programs instructed by Teacher (Program Re- Write
Practice). We have done this practice for six years and
investigated various kinds of result in order to acquire the
effect objectively. In this paper, we explain about
Program Reading Practice briefly at first. After that, we
describe about the investigation way and the several
results of our practice as follows.