I saw a paper years back, which I now fuzzily recall as having people select which size stones felt good, felt right in their hand, and then comparing that with their biophysics parameters like arm length, with a hypothesis that people like the feel of stones which are optimally sized for them to throw. So among thoughts of "innovation", perhaps include "thinking with your hands", and even beaver-style slapping mud on trickling noises "just because". Mens et manus (MIT's "mind and hand" motto).
