HILL is a pure bodyweight workout that consists of Squats, Mountain Climber and 10m Shuttle Run. You start with 50 reps per exercise (50x Squats, 50x Mountain Climber, 50x 10m Shuttle Run), then 40 reps per exercise, then 30 reps per exercise, then 20, then 10. One leg of Mountain Climber equals 1 rep, one 10m Shuttle Run equals 1 rep. The time cap for HILL is 30 minutes.
Scaling: You can scale HILL by decreasing the rounds and reps to 50-30-10.