I really do like these HIP (historically informed performance?) duos! haha I remember seeing some informative videos on their channel regarding interpretation of Sor's studies. Here's one:
For some reason, I guess from seeing their videos, I assumed that one was playing with nails and the other without. I've never read anything to lead me to believe that, though, just something that I subconsciously decided. There are other duos that are formed that way, the Schneiderman-Yamaya Duo, for example.
"One should always eat muffins quite calmly. It is the only way to eat them."