I visited the annual toy industry Toy Fair in London yesterday. It's a huge trade show in Earl's Court Olympia where toy designers, manufacturers and distributors erect display stands and pitch their products to retailers.

It was the first time I've been, and all in all quite an exhausting experience.

Whilst all the big names you'd expect were there – Hasbro, Lego, Playmobil, Hornby, etc – often with huge stands and teams of sales staff, it was often the small one-man-band type stands that were most intriguing.

Of these, Wedgits was one that caught my eye. The product consists of bright, primary coloured plastic pieces that fit and lock together. Unlike Lego and other construction toys though, the locking mechanism isn't based on the friction you get from a tight fit. Instead it's a little more mathematical, and derives just from the geometry of the pieces and the way they wedge together.

To be honest, even having seen it being demonstrated a few times, I still don't quite fully understand how it works, but the structures I saw being built and unbuilt were quite incredible.

The basis of the design is a simple Octahedron shape (imagine two square-based pyramids stuck together. Other larger bricks are based around a square with a rhombus-style cross-section, and share the same angles and widths, with the result that they stack together in interesting ways.

The product comes in two different scales, standard and 'mini', which is 40% smaller and is designed for slightly older children (5-12 instead of 2-10). I suspect the mini size is probably a little more fun, especially as you get more pieces for the same price.

There's lots more to say about the Toy Fair, but for me Wedgits represents one of the most fun and inspiring aspects of it: passionate people selling innovative products they've invented.