* Clocks 1 and 2: Got the sub-second updates working, currently 12
   per second blinking along edge of lower plane
* Clock 3: added progressive color change with each hand to indicate
   between-digit position, and also implemented a 5-second animation in
   the front plane using 5 squares: ea corner and the middle, one per
   second, plus the 12-per-sec animation around the edge of the front
   plane.  The color change is designed for max color difference: blue
   on yellow, red on white, etc.  this works well - BUT unfortunately,
   the hand planes are not clearly defined by a single color.
* Clock 4: same as 3 except I attempted to reduce color variation with
   each plane.  As colors progress within a hand, it now starts out
   with reduced saturation and brightness, and progresses to saturated
   color.
* Clock 5: Instead of using color saturation, use a blink to distinguish
   the  progression.  The hand starts out solid.
   the blink is 50% duty cycle 6 cycles/sec. As leds progress, I am
   using updateCountThisSec%0 > zero to gate between a darker version of
   the primary color and a full color with a bit added in the other 2 color
   channels, so saturation is reduced a bit and it gets brighter.
   UNFORTUNATELY this is rather blinky and distracting.