The p50 glider shuttle is a period-50 shuttle oscillator found in its original form by Dean Hickerson on March 3, 1992 and was the first period 50 oscillator to be discovered. Its original form used an early version of toaster and was based on a period 66 oscillator discovered by Robert Wainwright in September, 1984. The oscillator works by using two copies of eater 3 and four copies of a period-5 sparker (5blink would also work but only for periods 90 + 40n) found by Noam Elkies to shuttle two gliders back and forth. By increasing the distance between the two reflectors, oscillators of periods 50 + 40n can be created. In March, 1992 Hickerson created a related oscillator by crossing two pairs of gliders using rephasers, which allowed the construction of oscillators of periods 230 + 40n.
A related p230 oscillator discovered by Dean HickersonRLE: here