I found this via BleepLabs twitter. Had to try it out by myself.
All the necessary info is here:

little-scale.blogspot.com/2011/10/tweetable-one-loop-one-function-simple.html

From Little-Scale blog:

"In general, I guess we can call this "index modulation", in the sense that we have a counter (i) that keeps track of a loop. The sound output is calculated on a sample by sample basis using a function that manipulates i in various ways (left and right shifting, multiplication, divide, modulo etc). The combined output for each sample is then output to the R2R DAC where the value is converted to a voltage, which can be sent to a piezo, an amp or an audio input.

I find these ideas very exciting - it's a very minimalist approach to creating sound and music on a basic level, yet the outcomes are at times complex, containing rhythm, pitch and structure."

Indeed, very exciting.