Bipole tie pseudo-barberpole is a period-10 oscillator that is composed of a bipole and pseudo-barberpole that are diagonally touching. It was found no earlier than 1994. With a minimum population of 23 cells, it is the smallest known period 10 oscillator, though it is considered trivial because there is no individual cell that oscillates at the full period (as it is made up of a period 2 and a period 5 oscillator). The smallest known non-trivial period 10 oscillator, by minimum population, is 24P10.
- 23P10.1 at Heinrich Koenig's Game of Life Object Catalogs