[These pages were authored by the late Thoki Yenn,
and were restored here from the
by Erik Demaine
with contributions of missing files from various readers
(notably Tommy Stevens, Roberto Morassi, and Boaz Shuval).
If you spot any other bugs like missing images or pages,
please report them
Diagram was first publish more than 10 years ago in NOA magazine,
then later in falter 13, from where I have found some simple
early stuff from old times.