Karel's p15 is a period-15 oscillator discovered by Karel Suhajda on December 11, 2002. It consists of a period 15 rotor supported by the domino spark of a pentadecathlon. A pentadecathlon can support 2 Karel's p15s. It provides accessible sparks that can be used to perturb reactions. The p15 bouncer mechanism is an example. In the same month of its discovery, Mark Niemiec found an 18-glider synthesis of this oscillator.
Period 435 gun shows how this pattern thins out the glider stream and triples the period.
- 28P15.3 at Heinrich Koenig's Game of Life Object Catalogs