C.a.R. allows to make assignments to be solved by the student. Assignments are constructions with one or more target objects. The construction is displayed up to a given point, but all displayed objects are fixed. Target objects may or may not be shown in thin outline. The compute will check, if the student has solved the assignment. Only the target is checked, not the details of the construction.
In the assignment above a circle is to be constructed around M with radius AB. The tools are restricted to point, line and simple circle. Here is a solution.