The figure shows
four squares AA_{1}BA_{2}, BB_{1}CB_{2}, CC_{1}DC_{2}, and DD_{1}AD_{2}. Prove that
the quadrilaterals A_{1}B_{2}C_{1}D_{2} and B_{1}A_{2}D_{1}C_{2} are
congruent (same shape and size) parallelograms.
See
also:
Geometric art of
problem 1202 made with iPad
