This tiny "Blarplette" module is a shift register set up to be a tap programmable looping trigger. Its made from a 4031 CMOS chip which are a little tricky to find. I made a little video of it in action...if you don't want to hear me waffle about the patch then skip to around 2 minutes in.
New module 4031 tap looper from concretedog on Vimeo.