Which usually provides clues to 1 or more steps in a deductive proof. As far as the deductive reasoning is concerned, even a one step proof, even a proof that does not start with fundamental axioms, is a valid proof. In this context, the maxim that making the first step is the most difficult task is true in more than one sense. Proofs without words indeed very effectively help us not only learn mathematical statements but also develop a feeling for mathematics as a discipline. Those that permit some degree of interaction and experimentation are potentially even more effective.
Computers change the way mathematics is done, they change the way mathematics is taught and learned.
Computers provide a vehicle for the evolution of an interactive diagrammatic method. It does not include all PWWs which have appeared in print, but is rather a sample representative of the genre. In addition, as readers of the Association's journals are well aware, new PWWs appear in print rather frequently, and I anticipate that this will continue. I won't be surprised if the second volume of PWWs appears on CD-ROM or even online. Here is a simulation of an old puzzle.