Bad Piggies Ground Hog Day Bonus Level 1-VI (1-6) can be 3-starred in one step. Build a contraption using all the fans and the coil. Now navigate your vehicle down the hill until it reaches the star box. Let your vehicle roll back down the tunnels towards the finish line within the time limit. Use the fans to increase the speed as needed.
If you have a different strategy for completing this level feel free to leave a comment below.