Tub-with-tail eater

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Tub-with-tail eater
x = 9, y = 6, rule = B3/S23 7b2o$3bo3b2o$2bobo$bobo$bo$2o! #C [[ THUMBSIZE 2 THEME 6 GRID GRIDMAJOR 0 SUPPRESS THUMBLAUNCH ]] #C Still life
Pattern type Constellation
Number of cells 12
Bounding box 9 × 6
Discovered by Unknown
Year of discovery Unknown

The tub-with-tail eater (or eater 5), commonly abbreviated to TWIT, is an eater composed of a block and a tub with tail.

It is capable of eating gliders from two perpendicular directions. Upon impact at the upper tip, the tub with tail becomes a melusine-like pattern, and then this trans-loaf with tail predecessor hits the block to restore the tub motif while triggering a grin. It is generally used to absorb gliders in situations where the standard eater is insufficient, particularly because of its edge-eating ability; an example can be found in p61 Herschel loop 2.

2bo10b$obo10b$b2o10b2$7bo5b$7bobo3b$7b2o4b2$11b2o$7bo3b2o$6bobo4b$5bobo5b$5bo7b$4b2o! #C [[ THUMBSIZE 2 THEME 6 GRID GRIDMAJOR 0 SUPPRESS THUMBLAUNCH ]] #C [[ THUMBSIZE 2 ZOOM 16 AUTOSTART GPS 5 PAUSE 2 T 10 PAUSE 2 LOOP 30 ]]
Tub-with-tail eater eating gliders from different directions (click above to open LifeViewer)
RLE: here Plaintext: here

The eater 5 can be constantly renewed and hassled with an eater 1, giving the eater/block frob.


Variants using different still lifes are possible. For instance, the block can be replaced with a more complicated catalyst, or extra catalysts like eater bridge eater and grin reagent can be added to perturb the block. Eaters created in this way form a significant proportion of Dean Hickerson's eater collection.

A commonly applicable 10×6 variant[1] uses a long hook with tail to catalyze the reaction, whose clearance at the top is one cell better than the block. This is shown below to the left. This improvement allows for quicker removal of the first natural glider from a Herschel, which can be used to compress Herschel loops with a period of 57~60; see for example p57 Herschel loop 1 and Simkin's p60.

If there is additional clearance requirement on the left or right, variants as a single still life with higher population are available. One is a 25-cell, 8×8 still life[2], which can be seen in the middle of R64 and a 21-glider synthesis for it was found by Martin Grant in July 2013.[3] Another 27-cell variant[4] found by Dave Greene on February 6, 2003 is named 7×9 eater for its bounding box with thinnest horizontal size, as shown below to the right. Both of these instances contain a boat part instead of the tub with tail, and the gliders hit it in specific ways to make an intermediate nine.

x = 10, y = 6, rule = B3/S23 3bo3b2o$2bobo3bo$bobo3bo$bo4bo$2o5b3o$9bo! #C [[ THUMBSIZE 2 THEME 6 GRID GRIDMAJOR 0 SUPPRESS THUMBLAUNCH ]] #C [[ THUMBSIZE 2 ]]
A variation of the tub-with-tail eater using a long hook with tail (click above to open LifeViewer)
RLE: here Plaintext: here
x = 18, y = 24, rule = B3/S23 bo$2bo$3o5$15bo$14bo$14b3o6$12bo3b2o$11bobo3bo$11b2o3bo$15bo$11b5obo$ 11bo4b2o$12b3o$14bob2o$15bobo! #C [[ THUMBSIZE 2 THEME 6 GRID GRIDMAJOR 0 SUPPRESS THUMBLAUNCH ]] #C [[ THUMBSIZE 2 ZOOM 12 ]]
7×9 eater, shown with incident glider lanes (click above to open LifeViewer)
RLE: here Plaintext: here

See also


  1. xs17_624871z25a8o
  2. xs25_c9b8o696z352w56
  3. Martin Grant (July 20, 2013). Re: Scratch Your Heads: Glider Synthesis of Bellman One (discussion thread) at the ConwayLife.com forums
  4. xs27_j5ogilmzd586221

External links