RF28B

RF28B
x = 13, y = 10, rule = B3/S23 3bo$2bobo7bo$3bo6b3o$9bo$9b2o3$bo$b2o$2o! #C [[ THUMBSIZE 2 THEME 6 GRID GRIDMAJOR 0 SUPPRESS THUMBLAUNCH ]] #C [[ AUTOSTART ]] #C [[ WIDTH 600 HEIGHT 400 ZOOM 16 GPS 7 PAUSE 2 T 28 PAUSE 2 LOOP 29 ]]
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Pattern type	Conduit
Conduit type	Converter
Input	R-pentomino
Output	B-heptomino
Number of cells	11
Step	Unknown
Recovery time (ignoring FNG if any)	33 ticks
Minimum overclock period (ignoring FNG if any)	Unknown
Spartan?	Yes
Discovered by	Dave Buckingham
Year of discovery	Unknown
Pattern files RLE rf28b.rle

RF28B is a converter that accepts an R-pentomino as input and produces an output B-heptomino 28 ticks later. Of nine major variants known as of the end of 2017, four versions are shown below. Most of these were discovered by Dave Buckingham between 1972 and the early 1980's.

x = 18, y = 77, rule = B3/S23 8bo$7bobo7bo$8bo6b3o$14bo$14b2o3$6bo$6b2o$5b2o11$8bo$o6bobo$3o5bo$3bo$ 2b2o3$6bo$6b2o$5b2o18$6bo$6b2o$5b2o4$2bo$bobo$o2bo$b2o11$6bo$6b2o$5b2o 5$10bo$9bobo$9b2o! #C [[ THUMBSIZE 2 THEME 6 GRID GRIDMAJOR 0 SUPPRESS THUMBLAUNCH ]] #C [[ AUTOSTART THUMBSIZE 2 GPS 7 ZOOM 10 HEIGHT 800 PAUSE 2 T 28 PAUSE 2 T 48 PAUSE 2 LOOP 49 ]]

(click above to open LifeViewer) RLE: here Plaintext: here

The top version above is part of the L156 Herschel conduit, but it can be replaced by the variant below it which produces a forward glider output. The third version can be combined with a boojum reflector or rectifier to clean up the block normally produced by the output B-heptomino. The fourth version is used in Paul Callahan's Herschel receiver.

A B-heptomino naturally evolves into a Herschel, as shown above -- but it leaves an extra block behind which must then be cleaned up before the circuit can be used again. To avoid this problem, in most cases a conduit such as BFx59H or BFx46B will be appended to the RF28B.

External links

• RF28B at the Life Lexicon
• My Experience with B-heptominos in Oscillators, by Dave Buckingham