Blinkenlights

[citation needed] The term has its origins in hacker humor and is taken from a famous (often blackletter-Gothic) mock warning sign written in a mangled form of German.

ODERWISE IST EASY TO SCHNAPPEN DER SPRINGENWERK, BLOWENFUSEN UND POPPENCORKEN MIT SPITZENSPARKEN.IST NICHT FÜR GEWERKEN BEI DUMMKOPFEN.

Such pseudo-German parodies were common in Allied machine shops during and following World War II, and an example photocopy is shown in the Jargon File.

The Jargon File also mentions that German hackers had in turn developed their own versions of the blinkenlights poster, in broken English:[1] ATTENTIONThis room is fullfilled mit special electronische equippment.

Also: please keep still and only watchen astaunished the blinkenlights.The Connection Machine, a 65536-processor parallel computer designed in the mid-1980s, was a black cube with one side covered with a grid of red blinkenlights; the sales demo had them evolving Conway's Game of Life patterns.

Lights on the front panel of a DEC PDP-8 (1965)
The Harwell Dekatron Computer does arithmetic at approximately human speed. Watching the lights allows one to follow the instructions and the changing data as it runs the Squares program displayed on the panels
Blinkenlights on the NSA 's FROSTBURG supercomputer from the 1990s
Typical LED pattern of a Thinking Machines CM-5