Secret printer dots
Since the 1980s most colour printers and photocopiers add a set of secret near-invisible dots to every page they print. The dots uniquely identify the origin and timestamp of that printout.
Apocalypse fuel
Ever see a post-apocalyptic film where people are driving cars years after the fall of civilisation? Sorry, car fuel doesn’t work like that.
Tunnelling through the Atlantic
Bridges go over water. Tunnels go under water. How about the Archimedes bridge, a hypothetical tunnel design that goes through water instead?
Ghost in the painting
Artists sometimes change or improve paintings by painting over old versions. Through careful examination or special imaging, we can sometimes see these ghosts of lost art again.
Invisible programming
The esoteric programming language Whitespace uses only three characters: tabs, spaces, and line breaks. That makes it effectively invisible to the naked eye.
Remote control animals
Something creepy for your Friday: attaching electrodes to animals’ brains so their movements can be controlled remotely.
Protect the train
According to the North American train whistle code, one long whistle then three short whistles means only one thing: it’s time to jump off the train and attach the torpedoes.
Eternal September
Usenet (the early online discussion network) saw a rush of new American users each September, when a new crop of students began university or college. But from 1993 on, the September never ended.
Left and right countries
Most of the world drives on the right side of the road, but some countries drive on the left. What happens at the borders between right and left countries?
Moving bridges
How many ways can you move a bridge to let boat traffic through? Well, you can lift it, fold it, curl it, retract it, tilt it, swing it, or submerge it.
Polyglot programming
Polyglot programmes run in more than one programming language at the same time. One example runs in C, PHP, and Bash; another one runs in a ridiculous 282 different languages.
Return to the fold
Since 2000, millions of hours of computer time have been donated by people around the world to determine how proteins fold in the human body. This may help to understand and treat Alzheimer’s, cancer, HIV, flu, and the coronavirus.
Burning runway
What do you do when a plane cannot land because of heavy fog? In WWII Britain, you set the runway on fire.
Thousand shoulders
How do you build a highway flyover without closing the road directly below it? In Indonesia, you build the pylons sideways and then rotate them into position.
Computer chip graffiti
The silicon chip pictured here is the central processor from a 1991 Hewlett-Packard 9000 700-series workstation. It contains 577,000 transistors… and a horse?
