Sawtooth 177
| Sawtooth 177 | |||||||||
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| Pattern type | Sawtooth | ||||||||
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| Number of cells | 177 | ||||||||
| Bounding box | 74 × 60 | ||||||||
| Expansion factor | 121 | ||||||||
| Discovered by | Maia Karpovich | ||||||||
| Year of discovery | 2015 | ||||||||
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Sawtooth 177 is a refinement of Sawtooth 181 obtained by rephasing the constituent guns. It is the smallest known sawtooth in terms of its minimum repeating population of 177.[1] A bounding-box-optimized variant, Sawtooth 195, has a repeating population of 195 and a bounding box of 62 × 56,[2] significantly smaller than the previous 79 × 55 record set by Sawtooth 201. By removing the 2 gliders, making all the blocks pre-blocks, and making the pentadecathlon 10 cells in a row, it is possible to make a sawtooth that has 152 cells, but the minimum repeating population is still 177.
The sawtooth functions by letting two glider streams of period 120 retract a block, created by collision with a spark from a 58P5H1V1, one cell at a time. The retracted block is deleted via interaction with a pentadecathlon, and the streams are allowed to return to the now-farther-away 58P5H1V1 to create another block.
The population is equal to 177 at generations 15, 6975, 849135, 102750495, 12432815055, ..., 58 (121n − 1) + 15, ..., giving an expansion factor of 121.
| Sawtooth 177 (click above to open LifeViewer) RLE: here Plaintext: here |
| Sawtooth 195[2] (click above to open LifeViewer) |
See also
References
- ↑ Maia Karpovich (October 27, 2015). Re: Smaller sawtooth (discussion thread) at the ConwayLife.com forums
- ↑ 2.0 2.1 Maia Karpovich (October 31, 2015). Re: Smaller sawtooth (discussion thread) at the ConwayLife.com forums