The pseudo-barberpole (or Achim's p5[1]) is a period-5oscillator that was found by Achim Flammenkamp on August 22, 1994.[2] With a minimum population of 15cells, it is the smallest known period 5 oscillator, followed by octagon 2 with 16 cells.[3][4] On October 23, 2002Gabriel Nivasch found a period 5 oscillator that consists of four radially symmetrically arranged halves of the pseudo-barberpole.[5]
As of February 2022, this is one of four 15-cell oscillators, and one of eight 15-cell periodic objects (still lifes, oscillators and spaceships) which are yet to arise naturally from an asymmetric soup on Catagolue, with the other three oscillators being the nonapole, phoenix with cavity and tripole tie snake.[6]
Goldtiger997 found a 16-glider synthesis based on a sample soup from Adam P. Goucher's Catagolue on April 22, 2017.[7] Martin Grant found an unrelated 13-glider synthesis that can also act as a component on June 20, 2018.[8]
