That was the Alka-Seltzer moment, the moment when the tablet hits the water and begins to fizz.

I'd work eighteen-hour stretches and fall asleep in my clothes. Then I'd wake up in the middle of the night, brew a pot of tea, and start work again. I was tired, but work had become pure enjoyment.

All inventors, they say, are a little mad. I reckon that only completely sane people are willing to admit they are slightly crazy.

The key to success is to risk thinking unconventional thoughts. Convention is the enemy of progress.

Invention isn't some impenetrable brand of magic; anyone can have a go.

A good idea turns every cog in your mind, making you scared of bed in case the whole machine grinds to a halt.

Ideas for gadgets for the disabled were coming into my head so fast they seemed to be arriving from somewhere outside of me, beamed down by an unremitting force. I had little control over them, or their flow. I would wake up in the middle of the night. A blinding flash of an idea would rouse me from my bed and I'd rush down to my workshop to have a go at it before the inspiration dimmed.