Symmetrica / Still Lifes

The four most common still lifes are:

  1. Block
  2. Steeple
  3. Shell
  4. Carrier

Strict still lifes exist with every possible possible population except for 1, 2, 3, 5, and 8. The block, carrier, and steeple are the only still lifes with fewer than 8 cells. The only 8-cell still lifes are pseudo still lifes made up of two blocks.


  • Smallest still life, consisting of 4 cells
  • Most common object
  • Named after an identical object from the Game of Life

The block can “eat” a cell placed at one of its corners. This behavior appears in many oscillators, including beacon, dinner, and quartet.


  • 6-cell still life consisting of two chips
  • 4th most common still life
  • Named after an identical object from the Game of Life


  • 7-cell still life consisting of a block and a chip
  • 2nd most common still life


  • 14-cell still life
  • 3rd most common still life

The shell can eat a tugboat. It can also act as a one-time turner, reflecting a tugboat 180 degrees while getting destroyed in the process.

The table and its descendants are the most common predecessors of the shell.


  • 32-cell still life
  • Occurs in two variants: cis feast (left) and trans feast (right)

The feast is not very common, but it is more common than you would expect given its size. It is generated by two beehive sparks, allowing it to be easily constructed. The cis feast can also be generated by a tugboat and a blinker.

Both variants of the feast can eat a tugboat more efficiently than the shell. The cis feast can also act as a messy one-time 90 degree turner or duplicator. I have yet to investigate tugboat-trans feast collisions.