I'm off for a day on the water in a Benetau 25 and some PC work (different event) later.
I'll leave you for this weekend with a case send by Leif Nybom, an IU/IJ from Finland:
To avoid contact the windward Blue changes course and keep clear of Yellow. (White shows Blue holding her course).
Is one of the boats breaking a rule?
I'll give you until Tuesday to come up with the answer.