p29 pre-pulsar shuttle (or prime[1]) is a period-29 shuttle oscillator discovered by David Buckingham on August 2, 1980,[1] making it the first oscillator of that period to be found. In terms of its 54 cells it is the smallest known period-29 oscillator.[2] The oscillator works by combining the 15-generation, two-tub pre-pulsar shuttle mechanism used in Eureka with a 14-generation pre-pulsar shuttle mechanism. Hassling pre-pulsars in this way was the only known way of constructing period 29 oscillators until the discovery of the p29 traffic-farm hassler. In September 1994 Bill Gosper found that two copies of pre-pulsar shuttle 29 could be used to hassle a pentadecathlon. Gosper used this to construct the p58 toadsucker.
Some variants of this shuttle are shown below. A 42-glider synthesis is known for one variant, 56P29.
A fully symmetric variant of this oscillator was first known to appear semi-naturally in December 2014, in a soup found by Richard Schank using apgsearch.[3]
Image gallery
 Generation 4 reveals two pre-pulsars (black) being hassled by a 15-generation mechanism (green) and a 14-generation mechanism (red). |
 A slightly larger version of this oscillator, 56P29, with just one pre-pulsar (black) and an alternate 14-generation stabilization (red) RLE: here |
 A much larger version of this oscillator with four pre-pulsars RLE: here |
See also
References
External links
- 54P29.1 at Heinrich Koenig's Game of Life Object Catalogs
