A $n$-[polyplet][1] is a collection of $n$ cells on a grid which are orthogonally or diagonally connected. The number of $n$-polyplets is given by the OEIS sequence [A030222][2]: $1, 2, 5, 22, 94, 524, 3031, \dots$ See below the five $3$-polyplets: [![enter image description here][3]][3] A polyplet will be called $1$-step vanishing on [Conway's game of life][4], if every cell dies after one step. We observed that for $n\le 4$, a $n$-polyplet is $1$-step vanishing iff $n \le 2$. We found $1$-step vanishing polyplets with $n=9, 12$, see below: [![enter image description here][5]][5] **Question**: Is there an other $1$-step vanishing $n$-polyplet with $n \le 12$? If yes, what are they? (note that there are exactly $37963911$ $n$-polyplets with $n \le 12$). We can build infinitely many $1$-step vanishing polyplets with such pattern, see below with $n=142$: [![enter image description here][6]][6] *Bonus question*: Are there $1$-step vanishing polyplets of an other kind? [1]: http://www.conwaylife.com/w/index.php?title=Polyplet [2]: https://oeis.org/A030222 [3]: https://i.sstatic.net/1w6KD.png [4]: https://en.wikipedia.org/wiki/Conway%27s_Game_of_Life [5]: https://i.sstatic.net/1Xruj.png [6]: https://i.sstatic.net/VTELn.png