He found the first known c/5 diagonal spaceship, 295P5H1V1, in November 2000. He also has found several small c/4 diagonal spaceships, including crab, the current smallest-known such spaceship other than the glider.
He discovered 36P22, which is currently the smallest-known period 22 oscillator and led to the construction of the first known true period 22 gun. He discovered the first true period 36 glider gun and has contributed to the discovery of many interesting puffers and rakes.
He wrote the Oscillizer utility that analyzes oscillator patterns.
Patterns found by Jason Summers