10 rounds
Choose a set amount of calories as a target for each machine, each round - go for 10-20 cals each station and rest for the rest of each minute:
1min Row
1min Ski
1min Echo/Bike
1 rest

Variations:
Classic : Choose a set amount of calories, stick to the amount each round.
Interval: Every other round alt. between Cal. ⬆️ & Cal. ⬇️
Pyramid : Start light (ex. 7 Cal. ) and every round - increase with 1 Cal. until failure on one machine. Then gradually decrease the Cal. again.
Active recovery : "Chill mode pace", you should be able to chit chat with bestie for 10 rounds. 😁