The first 30 examples are mainly from the following books 
[A], [B], and [C]:<p>

    [A] "Proofs without Words: Exercises in Visual Thinking
        (Classroom Resource Material)", Roger B. Nelsen, 1993.
<p>
 
   [B] "Proofs Without Words II: More Exercises in Visual Thinking
        (Classroom Resource Material)", by Roger B. Nelsen, 2001.
<p>

   [C] "Math Made Visual", by Claudi Alsina and Roger B. Nelsen, 2006.