GUARINIS PROBLEM
Guarini, an Italian Mathematician, invented this puzzle in 1512
Two green frogs sit on the toadstools, A and C.
Two brown frogs sit on the toadstools marked F and H.
Each toadstool can only hold one frog at a time.
The frogs can only move along straight lines and have to change
places. How many moves are needed?
Invent similar puzzles of your own, perhaps with different numbers
of frogs.