A beautiful LED Pendant that incorporates a pushbutton as a simple mode selector.
I've made or assisted with putting about 15 of these pendants together and this project was the focus of the May 2017 class "Get Crafty (with Electronics!)" I taught at Collaborative Research Association of Social Hacktivity (Crash Space).
Since then, my personal piece has gone through a few iterations and now sports four additional rings.
Check out my Resplendr Pendant instructable.