|View static image|
|Pattern type|| Strict still life |
|Number of cells||19|
|Discovered by||David Buckingham|
|Year of discovery||Unknown|
Eater 2 (or block on hat siamese hat) is an eater that was found by David Buckingham in the 1970s. Mostly it works like the standard eater (see eater 1) but with two slight differences that make it useful despite its size; it takes longer to recover from each bite and it acts like an eater in two directions. The first property means that, among other things, it can eat a glider in a position that would destroy an eater 1. This novel glider-eating action is occasionally of use in itself, and combined with the symmetry means that an eater 2 can eat gliders along four different paths.
An eater 2 variant noticed by Stephen Silver in May 1998 that is useful for obtaining smaller bounding boxes is shown below. Note that the canonical version of eater 2 is a strict still life because the outside 15-cell component is not stable without the block (it is, rather, an inductee), but the eater 2 variant below is a pseudo still life because it is made up of an aircraft carrier, block and hat, each of which are stable.
Eater 2 can also be used to eat objects other than gliders. For example, one of them can eat a lightweight or middleweight spaceship, two of them can eat a 60P5H2V0, two or three of them can eat the bulk of a 2-engine or 3-engine Cordership respectively, and seven of them can be arranged to eat the majority of the 7-in-a-row Cordership.
It serves as the logo of Catagolue.
On January 29, 2004 Mark Niemiec found a 9-glider synthesis of a variation of eater 2 that consists of a hat, a block, and a table. On October 9th, 2014, David S. Miller found a natural eater 2 in a soup from Adam P. Goucher's apgsearch script, from which Tanner Jacobi derived a 6-glider synthesis.
- Eater 3
- Eater 4
- Eater 5
- Period-44 MWSS gun where an eater 2 variant facilitates the evolution of MWSSes.
- Buckingham's p13