This is a wonderful puzzle which requires a person to think in three dimensions. Most people seem to find it easier (and more fun) to start by working with physical pieces on a grid. I’ve introduced it to classes as young as grade 5, and to individual students younger than that.

Here are:

- a description of pieces and a template for the grid
- the process I use to introduce Towers to a group, which you might also use to help you figure it out for yourself
- the step-by-step solution for the example in the introduction
- a set of Easy 4×4 puzzles, which can be solved using the blocks
- a set of Medium 4×4 puzzles, which can also be solved using the blocks
- a set of Hard 4×4 puzzles, for which you might want to get out a pencil and eraser, although they can be solved using the blocks
- a set of Easy 5×5 puzzles

I’ll post more 5×5 puzzles soon!

You will find many puzzles of varying sizes and degrees of difficulty at Simon Tatham’s Portable Puzzles and at Brainbashers. There is also a commercial version called Utopia.