It was the Easter holidays, off to the various parents' for a few days, and Grandad had a surprise for #1 and #2 son - he took them to his school workshop to use proper power tools.
Of course, they needed to actually make something, so he prepared the parts they needed to make a wooden puzzle - The Tower of Hanoi.
Step 1: What you need.
Wood, and tools. Lots of both. When Grandad works in a high-school technology department, you can get both quite easily.
The boys used 15mm-thick MDF for the base, 5mm thick MDF for the puzzle-pieces and 5mm dowel for the posts.
The tools they used included coping saws, tenon saws, scroll-saws, files, glass-paper, a pedestal drill, power-sander, band-saw, circular saw and a mallet.
Oh, and goggles.