Every 3 minutes for as long as possible:
From 0-3 minutes: 2 rounds of 10 overhead squats and 10 chest-to-bar-pull-ups
From 3-6 minutes: 2 rounds of 12 overhead squats and 12 chest-to-bar-pull-ups
From 6-9 minutes: 2 rounds of 14 overhead squats and 14 chest-to-bar-pull-ups
Same pattern continues a long as you can go until you fail to complete both rounds.