Attempt to finalise working handshake. Via simple echo response.
program now loaded onto ATMEGA328P on STK (i.e. two systems running the same code)
cube_id changed for each instance
testing 1>2, 2>3

Redesign of handshake because one path is not valid

I init                    other init

Send mycubeid                get a reply othercubeid
get a reply mycubeid            send othercubeid
send mycubeid                get a reply othercubeid

The data to be transmitted must be minimised if possible. Since waiting for the transaction over six faces could manifest long delays.

results: handshake working beautifully

need to test timings etc. further development can only continue with actual cube housing...