Anatomy of a Roll.

1. Set baby on back.

2. Place alluring toy to the side of aforementioned baby.

3. Watch baby throw opposite side leg and arm over body in direction of desired toy.

4. Due to exerted effort, weight distribution begins to shift.

5. Baby has now completed full 180 degree rotation.

6. Success!

7. Happy Baby!

Thanks and Gig 'Em!