Bandersnatch

Bandersnatch
x = 50, y = 46, rule = B3/S23 o$b2o$2o16$45bo$44bobo$44bobo$43b2ob3o$31b2o16bo$31b2o10b2ob3o$43b2obo 7$46b2o$37bo8b2o$36bobo$36bo2bo$37b2o$20b2o$19bobo$19bo24b2o$18b2o24b 2o5$35b2o$35b2o! #C [[ THUMBSIZE 2 THEME 6 GRID GRIDMAJOR 0 SUPPRESS THUMBLAUNCH ]] #C [[ AUTOSTART ]] #C [[ THUMBSIZE 3 ZOOM 21 WIDTH 800 HEIGHT 800 X 9 Y 9 GPS 40 LOOP 200 ]]
View static image
Pattern type	Stable reflector
Number of cells	49
Bounding box	32 × 28
Angle	0°
Repeat time	70
Colour	Colour-changing
Discovered by	Martin Grant Entity Valkyrie
Year of discovery	2020
Rules Outer-totalistic rules B3/S23 only # of rules 20 = 1 Isotropic rules B3/S23 – B3/S236i
Glider synthesis Fewest gliders 16† Catagolue-generated RLE synthesis Uploaded synthesis RLE bandersnatch_synth.rle †Can be constructed with 15 gliders using the reverse caber tosser universal constructor.
Pattern files Plaintext bandersnatch.cells RLE bandersnatch.rle
Identifiers apgcode xs49_y933zy066yioge2zwooy22596zz8kkm0mmy6cczx343

The Bandersnatch is a 0° stable color-changing glider reflector (a glider shifter) discovered by Entity Valkyrie on June 5, 2020 based on a reaction and periodic variant by Martin Grant. The repeat time is 70, slightly less than the syringe's repeat time of 78. Since it contains an eater 2, an eater 1, a loaf and four blocks, it is Spartan. The name is taken from Lewis Carroll's The Hunting of the Snark.

The day of its discovery, Goldtiger997 used this reflector to reduce the repeat time of the highway robber, and found a modification which is a periodic G-to-2G. Later that day, Tanner Jacobi used it to reduce the size of the period-70 glider gun, and Adam P. Goucher discovered that the glider produced by the Bandersnatch could be fed into a nearby rectifier to produce an efficient merge circuit. On June 10, Sphenocorona constructed a p143 Bandersnatch loop using two Bandersnatches and two copies of 66P13. On January 3, 2022, iNoMed reduced this to create a Bandersnatch loop supported entirely by relatively small still lifes.

The Bandersnatch was voted Pattern of the Year for 2020 on the ConwayLife.com forums, tied with the Speed Demonoid.

Deriatives

Based on the main reaction and catalysts aforementioned above, a variant of BF20H was found that emits an extra glider.

x = 41, y = 35, rule = B3/S23 39bo$38bobo$38bobo$39bo$28bo$20b2o6bo$21b2o5b3o$20b2o8bo$20bo8$26b2o$ 2b2o22b2o$bobo$bo$2o$bob2o10b2o$o2bobo8bo2bo$2o2bo9bobo$15bo4$25b2obo $10b2o13b2ob3o$10b2o19bo$17b2o6b2ob3o$17b2o7bobo$26bobo$27bo! #C [[ THUMBSIZE 2 THEME 6 GRID GRIDMAJOR 0 SUPPRESS THUMBLAUNCH ]] #C [[ THUMBSIZE 2 ZOOM 10 WIDTH 480 HEIGHT 640 GPS 20 THEME Book AUTOSTART T 0 PAUSE 2 T 20 PAUSE 2 T 167 PAUSE 2 LOOP 168 ]]

BF20H variant based on the Bandersnatch reaction (click above to open LifeViewer)

Gallery

x = 58, y = 49, rule = B3/S23 obo18bo$b2o16b3o$bo16bo$18b2o$44bo$42b3o$41bo$41b2o6$4b2o45bo$4b2o43b 3o$48bo$48b2o$26b2o$15b2o9b2o$14bo2bo$15bobo$16bo3$38b2o$3bob2o31b2o$b 3ob2o13b2o$o19b2o$b3ob2o6b2o$3bobo7b2o$3bobo$4bo$56bo$55bobo$56bo4$46b 2o3b2o$46b2o3b2o3$38bob2o$36b3ob2o$35bo11b2o$36b3ob2o5bo$38bobo7b3o$ 38bobo9bo$39bo! #C [[ THUMBSIZE 2 THEME 6 GRID GRIDMAJOR 0 SUPPRESS THUMBLAUNCH ]] #C [[ THUMBSIZE 2 ZOOM 8 HEIGHT 500 GPS 40 THEME Book AUTOSTART T 0 PAUSE 1 T 330 PAUSE 5 LOOP 331 ]]

A connection to the boojum reflector with a shared block catalyst (click above to open LifeViewer)

x = 44, y = 31, rule = B3/S23 obo$b2o$bo3$25b2o$25b2o4b2o$17b2o12bo$17b2o10bobo$29b2o$36bo2b2o$35bob o2bo$35bobobo$34b2obob2o$33bo2b2o3bo$32b3o3b2o2bo$32b3o2b2obobo$18bo4b o8b3o3b2obo$19b2obobo8bo2b2o$18b2o2bo2bo8b2obob5o$23b2o10bobo2bo2bo$6b 2o27bo2bo$5bobo28b2o$5bo24b2o$4b2o24b2o5$21b2o$21b2o! #C [[ THUMBSIZE 2 THEME 6 GRID GRIDMAJOR 0 SUPPRESS THUMBLAUNCH ]] #C [[ THUMBSIZE 2 ZOOM 8 HEIGHT 500 GPS 40 THEME Book AUTOSTART T 0 PAUSE 1 T 70 PAUSE 1 T 132 PAUSE 5 LOOP 140 ]]

A p5 solution by Martin Grant (click above to open LifeViewer)

See also

• Snark
• Boojum reflector
• 0-degree colour-preserving reflector (March 2023)

External links

• Bandersnatch at Adam P. Goucher's Catagolue (pseudo-object)
• Bandersnatch at Wikipedia (name origin)