Dead spark coil

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Dead spark coil
x = 7, y = 5, rule = B3/S23 2o3b2o$obobobo$2bobo$obobobo$2o3b2o! #C [[ THUMBSIZE 2 THEME 6 GRID GRIDMAJOR 0 SUPPRESS THUMBLAUNCH ]] #C Still life
Pattern type Strict still life
Number of cells 18
Bounding box 7×5
Frequency class 16.3
Discovered by Unknown
Year of discovery Unknown

Dead spark coil is an 18-cell strict still life consisting of two mutually stabilising houses. It is one of three ways in which two houses can be arranged to create a still life, and one of the two which have two separate islands.

Skewing the two constituent houses gives rotated house, whereas connecting them diagonally to stabilise each other gives house bridge house.

One half of the dead spark coils can eat gliders, but both the top and bottom of that side must have a glider to eat, or else the other side of the house will interfere.


Dead spark coil is the forty-fifth most common still life in Achim Flammenkamp's census, being less common than trans-mirrored bun but more common than cis-mirrored bookend.[1] It is also the thirty-ninth most common object on Adam P. Goucher's Catagolue.[2]

Dead spark coils are typically formed when two pi heptominoes face each other three cells apart. If they are four cells apart, they instead form a live spark coil.

In D2 +1 symmetry, it is the 12th most common still life, being about 100 times more common than in an asymmetric soup, and it is the most common still life that takes advantage of symmetry to be much more common.

Glider synthesis

All strict still lifes with a population of 20 or fewer cells, as well as all oscillators and spaceships with 16 or fewer cells, are known to be glider-constructible. A glider synthesis of this object can be found in the infobox to the right.

In other rules

In HighLife, dead spark coil is an oscillator in much the same way as spark coil is, with a single-cell on-off rotor (a rotor impossible in Life due to all birth conditions being a subset of the survival conditions).

See also


  1. Achim Flammenkamp (September 7, 2004). "Most seen natural occurring ash objects in Game of Life". Retrieved on January 15, 2009.
  2. Adam P. Goucher. "Statistics". Catagolue. Retrieved on June 24, 2016.

External links