Bookends

	Bookends
	<a href="/wiki/File:Bookends.png" class="image" title="Bookends image"><img alt="Bookends image" src="/w/images/0/0c/Bookends.png" decoding="async" width="145" height="97" /></a>
	<a href="/wiki/File:Bookends.png" class="image" title="Bookends image"><img alt="Bookends image" src="/w/images/0/0c/Bookends.png" decoding="async" width="145" height="97" /></a>
	View static image
Pattern type	Strict still life
Number of cells	14
Bounding box	7×4
Frequency class	18.7
Discovered by	Unknown
Year of discovery	Unknown
Rules
Outer-totalistic rules	B/S23 – B378/S012345678
Important rules	Conway Life
# of rules	210 = 1024
Isotropic rules	B/S2aek3nr – B2in34-i5-jq6-i78/S012345678
Glider synthesis
Fewest gliders	4
Catagolue-generated RLE	bookends_synth.rle
Uploaded synthesis RLE	bookends_synth.rle
Pattern files
Plaintext	bookends.cells
RLE	bookends.rle
Identifiers
apgcode	xs14_39e0e93
Niemiec ID	14.590
Pentadecathlon ID	14.112

Bookends (or cis-mirrored hook) is a still life composed of two bookends.

Commonness

Bookends is the forty-sixth most common still life in Achim Flammenkamp's census, being less common than dead spark coil but more common than elevener.^[1] It is also the fifty-third most common object on Adam P. Goucher's Catagolue.^[2]