[FoRK] it's cells all the way down

Eugen Leitl eugen at leitl.org
Tue May 29 05:45:51 PDT 2012


A video of Conway's Game of Life, emulated in Conway's Game of Life.

Inspired by this video: http://www.youtube.com/watch?v=QtJ77qsLrpw I made a similar video, but with the speed and scale varying smoothly over time, rather than in discrete jumps as the original video did.

The life simulator used is Golly - http://golly.sourceforge.net/ which has a built-in script to generate these metapixel grids (select a pattern, and choose "metafier.py" from the scripts list). For more information about the metapixel pattern, see http://otcametapixel.blogspot.com/

The actual video is exported from Golly using a custom Python script: http://pastebin.com/8vVGCgKE (since Golly built-in only supports rendering the view with a scale which is a power of 2, for performance reasons - this is not a particularly well-optimised or fast script to run).

The audio track is a Shepard Tone: http://en.wikipedia.org/wiki/Shepard_tone
This is also generated by a Python script: http://pastebin.com/vxVeNtWc

Film & Animation

    Conway's Game Of Life (Game)


Creative Commons Attribution license (reuse allowed)


OTCA metapixel
OTCA metapixel
OTCA metapixel image
Pattern type 	Miscellaneous
Number of cells 	64691
Bounding box 	2058×2058
Discovered by 	Brice Due
Year of discovery 	2006
Pattern files
RLE 	otcametapixel.rle

The OTCA metapixel is a 2048 × 2048 period 35328 unit cell that was constructed by Brice Due between the autumn of 2005 and the spring of 2006. It has many advantages over the previous-known unit cells such as the p5760 unit Life cell and deep cell, including the ability to emulate any Life-like cellular automaton and the fact that, when zoomed out, the ON and OFF cells are easy to distinguish (the ON version of the cell is shown to the right and the OFF version of the cell is shown below).

It is designed to run quickly under the Hashlife algorithm, and thus Golly is generally used to view and/or manipulate meta-patterns made up of OTCA metapixels (and some such patterns even come packaged with Golly).

To tile these unit cells to emulate other patterns, place them so that the cornermost blocks overlap; the unit cells will physically overlap by 5 cells in every direction. The overlap will place tubs inside cross-corner neighbours.

    1 Details
    2 Image gallery
    3 Videos
    4 External links


The metacell uses a period 184 tractor beam, which acts as a clock. It pulls a block downwards by eight cells per impact, releasing a glider in the process. Some of the gliders are utilised; the rest are eaten. When the block reaches the base, it is restored at the top to begin the cycle again. Period 46 and 184 technologies (which are compatible) are used extensively throughout the configuration.

The rule is encoded in two columns, each of nine eaters, where one column corresponds to the 'Birth' rule and the other corresponds to 'Survival'. The nine eaters correspond to the nine different quantities of on cells (0 through 8). The presence or absence of the eater indicates whether the cell should be on in the next meta-generation. The state of the eater is read by the collision of two antiparallel LWSSes, which radiates two antiparallel gliders (not unlike an electron-positron reaction in a PET scanner). These gliders then collide into beehives, which are restored by a passing LWSS in Brice's elegant honeybit reaction. If the eater is present, the beehive would remain in its original state, thereby allowing the LWSS to pass unaffected; if the eater is absent, the beehive would be restored, consuming the LWSS in the process. Equivalently, the state of the eater is mapped onto the state of the LWSS.

When the display is 'on', two perpendicular waves of LWSSes collide, mutually annihilating each other. These streams of LWSSes are generated from an out of the blue reaction, triggered by passing HWSSes. 

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