1. Pancake Sorting
Input: Stack of pancakes, each of different sizes
Output: Arrange in order of size (smallest on top)
Action: Slip a flipper under one of the pancakes and flip over the whole stack above the flipper 3 2
finish 4 1 1
start 2 3 4

2. A Flip
Action: Slip a flipper under one of the pancakes and flip over the whole stack above the flipper 3 2 4
flip here 1 4 2 3 1

3. How? 1 2 3 4 2 2 4 3 1 1 4 3 3 1 1 3 2 2 4 4 5 6
Done! 2 1 1 2 3 3 4 4

4. For n pancakes, at most 2(n-1) flips
More Pancakes? 2 4 5 1 6 3
For n pancakes, at most 2(n-1) flips