- 114 - Investigating the number of ways to fill a row with separated blocks that are at least three units long
- 115 - Finding a generalisation for the number of ways to fill a row with separated blocks
- 116 - Investigating the number of ways of replacing square tiles with one of three coloured tiles
- 117 - Investigating the number of ways of tiling a row using different-sized tiles

These all flow from 114, and the secret there is to use recursion to try to fill the space to the right. Donâ€™t forget to memoize the recursion function.