Mind Games: The numbers Gaelic football referees are required to master

Stephen O'Brien, Barry O'Sullivan, Ryan Wylie and Ger Egan are just four inter-county footballers who claim the new experimental rules will be a burden on referees.

If it's not measuring the 20 metres that must be kicked from outside the opposition's 45-metre line to inside it, it's keeping count of three consecutive handpasses, a process that restarts over and over, while ensuring no fouls are being committed, maybe administering the five-second advantage rule and keeping an eye on other areas of the field.