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Snake-in-the-box updates
William Echols · Last updated September 4, 2026
This page collects my snake-in-the-box record improvements, along with selected updates from Tom Ace and others for chronological context. It is not intended to be a complete history. For the latest results, I recommend Ace's Snake-in-the-Box lower bounds.
Updates
- June 26-29, 2026 · Echols (more details)
- 12-d snake: 1461→1463
- 13-d snake: 2892→2898
- 10-d coil: 366→370
- 11-d coil: 694→700
- 12-d coil: 1346→1352
- 13-d coil: 2600→2624
- 11-d symmetric coil: 662→674
- July 2, 2026 · Echols (more details)
- 11-d symmetric coil: 674→718
- 12-d symmetric coil: 1222→1422
- 13-d symmetric coil: 2354→2766
- July 8, 2026 · Echols (more details)
- 13-d snake: 2898→2900
- 13-d coil: 2832→2840
- 12-d symmetric coil: 1422→1430
- 13-d symmetric coil: 2766→2810
- July 16, 2026 · Orland et al (A Census of New Snake-in-the-Box Records)
- 9-d snake: 190→191
- 10-d snake: 376→379
- 11-d snake: 737→746
- 12-d snake: 1465→1476
- 13-d snake: 2900→2922
- 9-d coil: 188→192
- 10-d coil: 370→374
- 11-d coil: 728→732
- 12-d coil: 1442→1466
- 10-d symmetric coil: 362→370
- 11-d symmetric coil: 718→726
- July 17, 2026 · Ace
- 13-d snake: 2922→2928
- 11-d coil: 732→734
- July 22, 2026 · Echols
- 13-d snake: 2928→2932
- 11-d coil: 734→736
- 12-d coil: 1466→1468
- Built from stale 2924- and 732-length starting records, as I was working over ssh and had not loaded Ace's latest results.
- July 23, 2026 · Ace
- 11-d coil: 736→738
- July 23, 2026 · Echols
- 11-d coil: 738→740
- August 11, 2026 · Ace
- 11-d snake: 746→747
- August 13, 2026 · Echols
- 13-d coil: 2916→2926
- 11-d symmetric coil: 726→730
- 13-d symmetric coil: 2810→2822
- Found by augmenting my approach with a neutral move from Ace.
- August 29, 2026 · Echols
- 11-d snake: 747→750
- 13-d coil: 2926→2930
- 12-d symmetric coil: 1430→1434
- 13-d symmetric coil: 2822→2830
Last updated September 4, 2026