For 40 minutes ascend the ladder as far as possible:

5 wall balls (9/6 kg)
10 double unders
150 m run or 10/8 cal ski
20 s rest

10 wall balls (9/6 kg)
20 double unders
300 m run or 20/16 cal ski
40 s rest

15 wall balls (9/6 kg)
30 double unders
450 m run or 30/24 cal ski
60s rest
etc…