siffrin's p103

siffrin's p103
x = 42, y = 42, rule = B3/S23 15bo$14bobo$15bo6$15b3o$15b2obo$15b2o2bo$16bob2o$15b3o2$bo$obo5b3obo$bo6b5o$8bo3bo$9bobo$10b2o3$30b2o$30bobo$29bo3bo$29b5o6bo$29bob3o5bobo$40bo2$24b3o$22b2obo$22bo2b2o$23bob2o$24b3o6$26bo$25bobo$26bo! #C [[ THUMBSIZE 2 THEME 6 GRID GRIDMAJOR 0 SUPPRESS THUMBLAUNCH ]] #C [[ AUTOSTART ]] #C [[ HEIGHT 560 ZOOM 12 GPS 12 ]]
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Pattern type	Oscillator
Number of cells	68
Bounding box	42 × 42
Period	103 (mod: 103)
Heat	28
Volatility	0.98 | 0.98
Kinetic symmetry	xk
Discovered by	siffrin normal
Year of discovery	2026
Rules Outer-totalistic rules B3/S23 – B3/S238 # of rules 21 = 2 Isotropic rules B3/S23 – B3/S236i8
Glider synthesis Fewest gliders 58† Catagolue-generated RLE synthesis †Can be constructed with 15 gliders using the reverse caber tosser universal constructor.
Pattern files Plaintext siffrinsp103.cells RLE siffrinsp103.rle
Identifiers apgcode xp103_ya252zyboo8gz0gy957423z121y17bjq7zypgc48gzykgggw31333y1252zyi358fezymgzyl121 Pentadecathlon ID 68P103

siffrin's p103 is a period-103 oscillator found by siffrin normal on February 21, 2026. It consists of four copies of an unnamed active object and four tubs acting as rocks, and produces two internal unnamed sparks. With 68 cells, it is the smallest known period-103 oscillator, well below the 180-celled syringe-based loop.

Discovery

A variant with long boats instead of tubs was found in the H4_x4 symmetry (the GPU-filtered counterpart of D4_x4), shortly after GPU searching with diagonal symmetry and 90° rotations was implemented in apgsearch.

x = 32, y = 32, rule = B3/S23 bo2b5ob5o3b2ob2ob2ob2obo$o3bo2b2obobob5obobo3bob2obo$2b6o2b2o4bob2ob3o3b4o$2b4o2b2o4b3obo2b6ob4o$5o5bo3b3ob2obo5bobobo$ob2obobo3b4obob2ob2o3bobobo$obo3b2ob2o2b4o3b2o3bo2bo2bo$3o2b7obob3o3b2obo3bo2bo$2obo3b5obo2b2ob2o2bo4b2o$3bo2b3o2b3obo5bo2bobob4o$3obob3ob2obo2b2o3b2ob6obo$obo2bob7obob2obo2bobo4bo$2o3bo3bobobo9bo2b2obobo$o4b10ob3obo5b6o$2ob4o6b6ob2ob2o5bo$bob2ob2obobo2bo2b2o2bob8o$b8obo2b2o2bo2bobob2ob2obo$bo5b2ob2ob6o6b4ob2o$6o5bob3ob10o4bo$obob2o2bo9bobobo3bo3b2o$bo4bobo2bob2obob7obo2bobo$ob6ob2o3b2o2bob2ob3obob3o$4obobo2bo5bob3o2b3o2bo$2b2o4bo2b2ob2o2bob5o3bob2o$o2bo3bob2o3b3obob7o2b3o$o2bo2bo3b2o3b4o2b2ob2o3bobo$bobobo3b2ob2obob4o3bobob2obo$obobo5bob2ob3o3bo5b5o$4ob6o2bob3o4b2o2b4o$b4o3b3ob2obo4b2o2b6o$ob2obo3bobob5obobob2o2bo3bo$bob2ob2ob2ob2o3b5ob5o2bo! #C [[ THUMBSIZE 2 THEME 6 GRID GRIDMAJOR 0 SUPPRESS THUMBLAUNCH ]] #C [[ AUTOSTART GPS 12 ZOOM 10 HEIGHT 560 THUMBSIZE 2 T 0 PAUSE 1 T 152 PAUSE 1 LOOP 153 ]]

The soup from whence it emerged (click above to open LifeViewer)

Synthesis

On February 23, 2026, Chris857 found a 76-glider synthesis of the long boat version from the soup result, along with a synthesis of the tub version which Evin reduced to 84 gliders. Chris857 further reduced the synthesis of the long boat version to 66 gliders and the tub version to 74 gliders, then to 58 gliders for the tub, long boat and barge versions.

External links

• Siffrin's p103 at Adam P. Goucher's Catagolue

• the first discovered form (with long boats instead of tubs)