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x = 29, y = 47, rule = B3/S23 19b2o$19bo$17b3o16$17b2o$17b2o2$8b2obo$8bob2o$26b2o$26bo$24bobo$24b2o 2$9bo$9b3o$o11bo$3o8b2o14bo$3bo22bobo$2b2o23bo7$bo$bobo$b3o$3bo11b2o$ 15bo$16b3o$18bo! ---- #C [[ THUMBSIZE 2 THEME 6 GRID GRIDMAJOR 0 SUPPRESS THUMBLAUNCH ]] #C [[ AUTOSTART ]] #C [[ ZOOM 8 GPS 10 LOOP 157 PAUSE 2 T 69 PAUSE 2 T 97 PAUSE 2 T 156 PAUSE 2 WIDTH 480 HEIGHT 480 THUMBSIZE 2 ]]
Pattern type Conduit
Conduit type Composite
Input Herschel
Number of cells 56
Output orientation Turned left
Output offset (17, -41)
Step 156 ticks
Recovery time
(ignoring FNG if any)
62 ticks
Minimum overclock period
(ignoring FNG if any)
Spartan? Yes
Dependent? No
Discovered by David Buckingham
Year of discovery 1996

L156 is a composite conduit, one of the original sixteen Herschel conduits, discovered by Dave Buckingham on August 7, 1996. It is made up of three elementary conduits: HLx69R, RF28B, and BFx59H. After 156 ticks, it produces a Herschel turned 90 degrees counterclockwise at (17, -41) relative to the input as well as an extra glider to southeast.

Its recovery time is 62 ticks. It can be made Spartan by replacing the snake with an eater 1 in one of two orientations. In the pattern shown in the infobox, a ghost Herschel marks the output location.


Three variants are shown below. The first is the one in the infobox. The second uses an alternative RF28B to emit a glider to northeast instead. The third uses a structure similar to RNE-19T84 to produce two extra gliders.

x = 74, y = 97, rule = B3/S23 19b2o38b2o$19bo39bo$17b3o37b3o16$17b2o38b2o$17b2o38b2o2$8b2obo36b2obo$ 8bob2o36bob2o$26b2o$26bo$24bobo$24b2o2$9bo39bo$9b3o37b3o$o11bo27bo11bo $3o8b2o14bo12b3o8b2o14bo$3bo22bobo14bo22bobo$2b2o23bo14b2o23bo4$64b2o$ 64bobo$66bo$bo39bo24b2o$bobo37bobo18b2o$b3o37b3o18bo$3bo11b2o26bo11b2o 6b3o$15bo39bo9bo$16b3o37b3o$18bo39bo4$59b2o$59bo$57b3o16$57b2o$57b2o2$ 48b2obo$48bob2o2$33b2o$33bo16bo$31bobo15bobo$31b2o16bobo$47b3ob2o20bo$ 46bo24b3o$40bo6b3ob2o17bo$40b3o6bob2o17b2o$43bo$18bo23b2o$16b3o48b2o$ 16bobo47bo2bo$16bo50b2o4$41bo$41bobo$30b2o9b3o$17b2o11b2o11bo11b2o$18b o36bo$15b3o38b3o$15bo42bo! #C [[ THUMBSIZE 2 THEME 6 GRID GRIDMAJOR 0 SUPPRESS THUMBLAUNCH ]] #C [[ AUTOSTART THUMBSIZE 2 ZOOM 10 WIDTH 800 HEIGHT 1000 GPS 16 PAUSE 2 T 73 PAUSE 2 T 97 PAUSE 2 T 156 PAUSE 2 LOOP 157 ]]
Three L156 variants. The third one is shown
following a Fx77. (click above to open LifeViewer)
RLE: here Plaintext: here

The third L156 variant is a period doubler because it produces an extra block that destroys the next Herschel. It can be deleted using either a reflector (such as the p8 bumper + dependent conduit) or a set of conduits (e.g. R64 + F117, at the cost of impractically high repeat time). In most cases where only the edge-shooting northeast glider is needed, it is better to suppress the output Herschel as in RNE-19T84.


On January 1, 2012, Matthias Merzenich found Lx138, a composite conduit consisting of HL79B and BFx59H.[1] The HL75B stage evolves identically to HLx69R until generation 69, when a block and an eater 2 absorb the southeast glider to transform the original R-pentomino to B-heptomino output.

x = 31, y = 38, rule = B3/S23 18b2o$19bo$19b3o16$20b2o$9bo10b2o$9b3o$o11bo14bob2o$3o8b2o14b2obo$3bo$ 2b2o3$24b2o$24b2o3$bo$bobo20b2obo$b3o20b2ob3o$3bo11b2o13bo$15bo8b2ob3o $16b3o4bo2b2o$18bo4b2o! #C [[ THUMBSIZE 2 THEME 6 GRID GRIDMAJOR 0 SUPPRESS THUMBLAUNCH ]] #C [[ WIDTH 500 HEIGHT 500 ZOOM 12 AUTOSTART GPS 10 PAUSE 2 T 69 PAUSE 2 GPS 5 T 79 PAUSE 2 GPS 10 T 138 PAUSE 2 LOOP 139 ]]
Lx138 Herschel conduit (click above to open LifeViewer)
RLE: here Plaintext: here


+ Rf28b.png
+ Conduit1.png
The elementary conduits that form L156

See also


  1. Matthias Merzenich (January 1, 2012). Re: Finally trying out stable Herschel tracks... (discussion thread) at the ConwayLife.com forums

External links