This lesson was about Fibonacci numbers. I introduced the lesson as a challenge, for them to work in groups through a set of mysterious puzzles in envelopes. Each numbered envelope contained one puzzle, and students had to successfully complete one puzzle before moving to the next. Each puzzle had a clue, but groups had to agree that they were stuck before they could look at it. The topics we explored through these puzzles included:
Fibonacci numbers, Fibonacci squares, Fibonacci rabbits, the Pascal triangle and the Golden Ratio.