Y cable ?

In the inspection it asks Robot uses 1 y cable per each 3-wire motor port dose it mean one y cable for a port or can you use more than one to branch of each other. EX you start with a y cable then branch off to two more y cables then to motor controls.

I think rule <R12> might answer your question (emphasis mine):

Essentially, the intent of the rule is that you don’t overload the Cortex by having one port controlling too many motors. So while in theory you could still branch the Y-cable as long as you don’t have one Cortex port controlling more than 2 motors, I can’t think of any situation where that would actually be necessary (or unable to be accomplished using wire extensions).