“Flight simulator”

5-10-15-20-25-30-35-40-45-50-45-40-35-30-25-20-15-10-5

Double unders unbroken

Or, if you don’t have d.u.,

10-20-30….100-90-80…10 single unders

If you suck at d.u. don’t execute them unbroken or Work with multiple of 3