Fumarole is a period-5 oscillator that was found by Dean Hickerson on September 3, 1989. In terms of its 18 cells it is the fourth smallest period 5 oscillator, after pseudo-barberpole, octagon 2, and Silver's p5; however, its 7×8 bounding box is the smallest of any known period 5 oscillator. The domino spark that it provides makes it useful in the construction of higher period oscillators such as the p35 beehive hassler, p40 B-heptomino shuttle, and 98P25. On September 1, 1995, Noam Elkies found a way to non-trivially combine two fumaroles and a blinker into a period 10 oscillator, shown below; 4 can be combined in a similar fashion. In February 2000 Stephen Silver found a 7-glider synthesis of this oscillator.
On Catagolue, it is the second most common period 5 oscillator, being less common than octagon II but more common than Elkies' p5.
- 18P5.1 at Heinrich Koenig's Game of Life Object Catalogs