Sawtooth 260

Sawtooth 260 is a diagonal sawtooth that was discovered by David Bell on March 19, 2010. It was the smallest known sawtooth in terms of its minimum repeating population of 260 up until January 26th, 2015.

Sawtooth 260
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Pattern type Sawtooth
Number of cells 260
Bounding box 154×100
Expansion factor Unknown
Discovered by David Bell
Year of discovery 2010

The pattern works by using 180-degree glider reflections from the 4-engine Cordership. Two figure eights are used to delete two outbound gliders with each returning glider.

On January 26th, 2015, Chris Cain discovered a way to use a blocker and a snake in places of the two figure eights, reducing the minimum population by to 252.[1] 4 days later, Dave Greene moved the blocker so that the snake could be removed, reducing the population to 246.[2] These variants have since been surpassed by other sawtooths such as Sawtooth 177, the current record holder as of January 2019.

Original form

The original form of this sawtooth was discovered on July 7, 2005. It used the slightly larger 3-engine Cordership at its top-left and had a minimum repeating population of 269. On July 9, 2005 David Bell found a related sawtooth with a minimum repeating population of 262 which used the 136-cell version of the 4-engine Cordership and a period-8 reflector instead of two figure eights.

  • The number of alive cells plotted versus the number of elapsed generations roughly forms an ever-increasing sawtooth graph.
  • The original form of this sawtooth used the 3-engine Cordership.
    RLE: here
  • A related sawtooth with a minimum repeating population of 262
    RLE: here
gollark: Ah yes, of course.
gollark: Maybe I should license my code under the PotatOS Privacy Policy, WTFPL, Unlicense, MIT, AGPL, Unicode, Inc. License Agreement for Data Files and Software, Apache License 1.1, CeCILL-B version 1, EUPL 1.2, and Nokia Open Source License simultaneously.
gollark: It's too vague and meaningless.
gollark: Alternative Idea: use the "RealNetworks Public Source License (RPSL), Version 1.0".
gollark: Idea: license all your code under the "Unicode, Inc. License Agreement for Data Files and Software".

References
  1. Chris Cain (January 26, 2015). Smaller sawtooth (discussion thread) at the ConwayLife.com forums
  2. Dave Greene (January 30, 2015). Re: Smaller sawtooth (discussion thread) at the ConwayLife.com forums
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