Drifter
A drifter is a perturbation moving within a stable pattern.
Dean Hickerson has written a program to search for drifters, with the hope of finding one which could be moved around a track. Because drifters can be very small, they theoretically can be more tightly packed than Herschels. Before omniperiodicity was proven, searchers like Hickerson attempted to find new drifter periods to solve the remaining periods. Hickerson had found a number of components towards this end, but it has proven difficult to change the direction of movement of a drifter, and so far no complete track has been found. However, Hickerson has had success using the same search program to find eaters with novel properties, such as that used in diuresis.
dr, the search program used to find drifters, can also find oscillators. Most oscillators with period 10 or greater with dense stators and small rotors were found this way, including 55P10, p11 domino sparker, 66P13, three of the known base p17s, and Merzenich's p18. The highest period found with dr that doesn't rely on symmetry, flipping, or phase-shifting is 18 (Merzenich's p18); 19 is possible, but specific periods can't be directly searched for.
| Diagonal c/2 wire is an example of a drifter running along a barge extension. (click above to open LifeViewer) RLE: here Plaintext: here |
External links
- Drifter at the Life Lexicon
- Re: New p17 and other billiard tables (discussion thread) at the ConwayLife.com forums (download link)
- A small modification of dr (discussion thread) at the ConwayLife.com forums (Matthias Merzenich's modified version)
- dr Discussion Thread (discussion thread) at the ConwayLife.com forums (includes a hopefully up-to-date version of dr and its knownrotors file)