A Zen Master, a Zen Monk, a Zen Mathematician

摘要

Inspired by the RyAian-ji garden in Kyoto, we formulate and solve some problems on the arrangement of two sets of points in the plane. We imagine a Zen Master and a Zen Monk that want to create a dry garden: they will discover the importance of convexity and collinearity, as well as incidence and betweenness. We present these problems with a didactic exposition and we suggest some generalizations which require other mathematical tools.