The p43 Snark loop is a period-43 oscillator made from Snark reflectors. It is the smallest of an infinite family of Snark-based adjustable glider loops that can have any period from 43 up.
There are much smaller glider loops containing four gliders, with a total signal path length of 216+8n and therefore adjustable to any period of the form 54+2n. However, this is the smallest loop that can contain eight gliders, which is a requirement for universal adjustability.
A 226-glider synthesis of this oscillator was discovered by Jeremy Tan on June 9, 2019. This was reduced to 196 gliders on October 16, 2020 by MathAndCode and GUYTU6J, and then to 131 gliders in April 2021 by MathAndCode and Dave Greene.