Abstract
In this paper I describe a problem in Jewish religious law that involves the detection of various prescribed patterns in the menstrual cycles of a woman, which formed the basis of several student projects. It commences with a short description of the Jewish calendar followed by an introduction to the religious background. The various patterns described in the religio‐legal literature are then listed and the objectives of the program specified. Some of the problems in analysing the data are presented and an example of the required form of the output is given. The paper concludes with a discussion of how the problem might be used pedagogically as the basis of student programming projects at various levels.