We turn back to the metal casing to extract the pen nib and look for its sensor magic.

Peeling up one of the tiniest boards we've ever seen we find a set of three matching ticks. Three on the end of the pen assembly, and three on the tiny board.

If we had to hazard a guess, we'd say these helped sense pressure by measuring movement between these two parts.

Chances are this chip could tell us more about how this works...

It reads 8529043 343S00008-A1—likely a custom STMicroelectronics controller for the nib.