A stable pseudo-Heisenburp device is a design that detects the passage of a spaceship by reacting it with stable patterns and restoring the spaceship's original path and timing. These are considered "pseudo" because a true Heisenburp device does not even temporarily damage or affect a passing spaceship, yet can still produce an output signal in response.
True stable Heisenburp devices are possible with many other types of spaceships, but not with gliders which have no usable side sparks to initiate an output signal. Therefore stable pseudo-Heisenburp devices for a glider are of academic interest.
The first example was constructed by Dave Greene in January 2007, using a complex recipe found by Noam Elkies to insert a signal into a 2c/3 wire. The wire's high transmission speed allows a signal from a highway robber to catch up to a salvo of gliders. Ultimately the mechanism restores the key glider, which was destroyed by the highway robber in the first stage of the converter, to its exact original position in the salvo.
Much smaller stable pseudo-Heisenburp devices have since been designed that use simple 0-degree glider seed constellations instead of a 2c/3 wire. More recently, Martin Grant was able to simplify the 2c/3 signal insertion recipe considerably in September 2017, allowing for smaller converter circuitry which could also be used to reduce the size of the old pseudo-Heisenburp pattern.
A more recent method of creating pseudo-Heisenburp devices involves the use of one-time turners, which produce several output gliders when an input glider crashes into it, including one glider on the same lane and with the exact same timing as the original input. With this design there is no need for a 2c/3 wire to send a signal to catch up with the glider's location. The only problem is that the one-time constellation is used up by the collision, so the output signal(s) must be routed into factory circuitry to rebuild the constellation before the mechanism can be used again.
When a banana spark hits a loaf, it can turn a block into a glider plus an extra beehive. This property can be used to make a stable pseudo-Heisenburp for a 2-engine Cordership since they produce banana sparks in an accessible location.
- Adam P. Goucher (November 14, 2011). Re: Thread for Your Accidental Discoveries (discussion thread) at the ConwayLife.com forums
- Martin Grant (September 11, 2017). Re: Stable Signal Converters (discussion thread) at the ConwayLife.com forums
- Dave Greene (September 21, 2017). Re: Stable Signal Converters (discussion thread) at the ConwayLife.com forums
- Entity Valkyrie (November 24, 2018). Re: Thread For Your Accidental Discoveries (discussion thread) at the ConwayLife.com forums