Our opening quote contended that Venn diagrams are overrated. Even those who agree must admit that they have a curious allure. Take the sets of interesting topics in logic, in geometry and in ...

These run from \('2'\) to \('5'\). Initially the diagram is set up like the one above. The unit digits are now included by taking each number in turn \(36\) - we put a \(6\) in the \('3'\) line.