cisblockonlonghook_synthhttps://conwaylife.com/wiki/Cis-block_on_long_hook https://conwaylife.com/patterns/cisblockonlonghook_synth.rle 4-glider synthesis of cis-block on long hook, with other syntheses from Mark Niemiec's database at https://conwaylife.com/ref/mniemiec/12/12-28.rle