"Sorry, did I say something wrong?" said Marvin, dragging himself on regardless. "Pardon me for breathing, which I never do anyway so I don't know wh… - Douglas Adams

Joo Janta 200 Super-Chromatic Peril Sensitive Sunglasses have been specially designed to help people develop a relaxed attitude to danger. At the first hint of trouble, they turn totally black and thus prevent you from seeing anything that might alarm you.

The technology involved in making anything invisible is so infinitely complex that nine hundred and ninety-nine billion, nine hundred and ninety-nine million, nine hundred and ninety-nine thousand, nine hundred and ninety-nine times out of a trillion it is much simpler and more effective just to take the thing away and do without it.

R is a velocity of measure, defined as a reasonable speed of travel that is consistent with health, mental well-being, and not being more than, say, five minutes late. It is therefore clearly as almost infinite variable figure according to circumstances, since the first two factors vary not only with speed as an absolute, but also with awareness of the third factor. Unless handled with tranquility, this equation can result in considerable stress, ulcers, and even death.