finished all features and elements. All working well.

tap detection was confusingly simple. I spent hours trying to find the
code to detect a tap, then realized that I had already done it and
didn't connect the recognizer to the 'tap-event'. It was a
philosophical problem. I saw tap-events as something to detect (done by
the user), and functions as things to trigger in response to those
click-events. We need a better vocabulary for these things.