Tell the time with colours that change as they rotate round the clock face.
Blobs at the end of the hour, minute, and second regions change colours over
time (red = 12, yellow = 3, green = 6, blue = 9).
This might help younger children to tell the time without having to know what
numbers mean (e.g. it's yellow and orange).
A sine-wave second "tick" has also been implemented, as well as fixing the
minute hand to integer positions. This makes the clock a bit more interesting,
because each hand tells the time in a different way.
Other apps by this developer: https://f-droid.org/packages/org.gringene.concentricclock