Demo: http://dc25.github.io/metronomeElm/
This project/exercise started out as an implementation of the Rosetta code task "Metronome": http://rosettacode.org/wiki/Metronome . Along the way I decided to try implementing the graphics in SVG and for comparision purposes I left the original collage code/functionality in place.
The sound is a wooden spatula tapping a wooden cutting board.
I know a mechanical metronome is not exactly the intention of the person who wrote the Rosetta Code task but I thought it would be fun.