He wanted them to keep creating, so he started a company called Seven:Twelve Engineering and began designing a building toy that could hold the attention of these older kids. That toy is called Crossbeams, and it can be used to design and assemble a huge range of toys – including big, detailed, moving cars and helicopters.

Crossbeams are small, stiff, white tube-shaped bits of solid plastic. Some are curved or bent at one end. Others are completely straight. There are also special pieces like gears and wheels, and different kinds of joints. Crossbeams join together in two steps: first with a typical male/female connection in which one slides into the other, then with a ring that you twist 45 degrees to secure the joint against different kinds of stress and to allow your constructions to withstand up to 20 lb (9 kg) of normal force.

Each Crossbeam piece can be connected in any of eight different orientations, and there are over 40 piece types (including the joints), so there's a lot of flexibility in what you can produce. Having said that, most frames designed so far can be created from less than half that.