Hello, there's one error that I can't quite clear on the ARCS_teensy_sketch due to the Encoder.h file: In file included from C:\Users\....\ARCS_teensy_sketch.ino:195:0: Encoder.h: In function 'void loop()': C:\Users\.....\ARCS_teensy_sketch\Encoder.h:161:70: warning: local class 'class loop()::Encoder' shall not have static data member 'loop()::Encoder_internal_state_t* loop()::Encoder::interruptArgs [55]' [-fpermissive] static Encoder_internal_state_t * interruptArgs[ENCODER_ARGLIST_SIZE]; If there isn't a declared variable type in front of "Encoder_internal_state_t", it makes more errors. I tried changing the "static" variable type to a "volatile", got 60 errors for each interruptArgs[ ]. Thought maybe that variable may need to be made public, no luck either. public: Encoder_internal_state_t encoder; I can't run anything until I can resolve this error and download to the Teensy 4.1. Any thoughts? I put all three files into this Google Drive folder. Thank you.