Logic puzzles 5

Let's talk puzzles, shall we?....Logic puzzles are my favourite. They really give the brain a good workout. I have a Dell puzzle book with many of these in them, and I have them almost finished. The harder ones require lot's of time and mental energy to complete, as they always throw you for a loop because quite often, they present a puzzle within a puzzle. I admit at times to looking at the answer page to give myself a head start on the real hard ones. The easier ones are usually more linear, and the step up to the insane ones is gradual. They are a valuble learning tool and great fun as well. I don't recall these being in the curriculum at the schools I went to, but I think they would be a valuble learning tool in an increasingly complex world.