Jason Summers and I independently discovered a small pattern that acts like a period-38 c/2 "chaos puffer" -- it repeats after 38 generations with a chaotic mess behind it. It is shown below in two forms; the larger one is more robust to perturbations, but nevertheless is eventually killed off by the growing chaos behind it. The third pattern below is a larger almost-puffer found by Jason, that also eventually gets killed off by its own debris.
We don't know how to make a tame p38 puffer from these patterns. Fortunately, by perturbing the smoke very early, Jason was able to make spaceships of other periods, such as 8, 10, and 20:
He also found another chaos puffer perturbation, with period 24.
The p20 spaceship is easy to turn into a simple puffer that puffs 2 or 4 tubs:
It proved to be difficult to turn this into a rake (puffer that emits only gliders), but after considerable noodling around, Jason came up with this p40 example:
The rake about sends its gliders sideways, to the right. It would also be useful to send gliders forwards and backwards. Period 40 is not large enough to build a forward rake. Using a 3c/6 spaceship, the rake can be thinned out to p120, allowing a forward rake to be built. Jason thinks there's probably a better way to do this; e.g. using p4 c/2 spaceships to turn the 2c/5 spaceships.
Period 80 would also work, but we don't know how to build a p80 sideways rake. Here's a way to build a chaotic "p80" puffer based on de-phasing a p6 spaceship:
Now that we have rakes, it should also be possible to use them to construct breeders. However, since these rakes are unable to produce closely-spaced glider salvos directly, one would either need to combine forward and back rakes to make such salvos, or to use a gun synthesis that allows the gliders to come in one-at-a-time.
B35/S236 -- Cellular Automata -- D. Eppstein -- UCI Inf. & Comp. Sci.