With a continuously running clock, squat for 60 seconds. Subtract the number of squats completed from 60, and do that many pull-ups in minute two. In minute three, squat again, subtracting the number completed from 60. Do that number of push-ups in minute four. Minute five is squatting again, and minute six pull-ups.
The pattern is squats, pull-ups, squats, push-ups, squats, pull-ups, etc. The goal is to stay within the workout