Life Period-2 Pseudo-Oscillators

Size in cells: 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | Larger
Cost in gliders: 4 | 5 | 6 | 1 glider/bit | >1 glider/bit | unknown



The 1 ten-bit period 2 pseudo-oscillator

10b PP2

Block on beacon [4]


The 2 eleven-bit period 2 pseudo-oscillators

11-bit PP2

Up boat on beacon [4] Down boat on beacon [6]


The 14 twelve-bit period 2 pseudo-oscillators

12-bit P2 pseudo-oscillators

Up toad on toad [5] Down toad on toad [6] Up ship on beacon [6] Up cis carrier on beacon [7] Up snake on beacon [8] Up trans carrier on beacon [7] Up cis beacon on beacon [6]
Down snake on beacon [7] Down ship on beacon [6] Block on bipole [7] Beehive on beacon [5] Down trans carrier on beacon [7] Down cis carrier on beacon [7] Down cis beacon on beacon [6]


The 17 thirteen-bit period 2 pseudo-oscillators

13-bit period 2 pseudo-oscillators

Up beacon below eater [7] Up long boat on beacon [6] Down beacon above eater [5] Up beacon on eater [7] Up trans python on beacon [10] Up cis python on beacon [10] Up boat on bipole [6] Up loaf on beacon [6] Down loaf on beacon [6]
Down trans python on beacon [10] Down beacon below eater [7] Down beacon on eater [7] Down long boat on beacon [6] Block on tripole [9] Up boat on bipole [8] Up beacon above eater [5] Down cis python on beacon [10]  


The 46 fourteen-bit period 2 pseudo-oscillators

14-bit period 2 pseudo-oscillators


The 78 fifteen-bit period 2 pseudo-oscillators

15-bit period 2 pseudo-oscillators


The 225 sixteen-bit period 2 pseudo-oscillators

Due to space limitations, these and their syntheses are shown on a separate page.


The 484 seventeen-bit period 2 pseudo-oscillators

Due to space limitations, these and their syntheses are shown on a separate page.


The 1519 eighteen-bit period 2 pseudo-oscillators

Due to space limitations, these are shown without syntheses on a separate page. All of these can be synthesized using the same techniques that are used for smaller pseudo-oscillators and pseudo-still-lifes. Syntheses for 14 of them are shown here.

18-bit pseudo-P2

Trans trans beacon on beacon on beacon [10] Down bipole above cis hook w/ tail [28] Up cis tripole on tripole [26] Up trans tripole on tripole [16] Down boat on block on tripole [10] Down beacon below carrier bridge snake [17] Cis two up beacons on beacon [5]
Cis two beehives on beacon [5] Down bipole on cis shillelagh [25] Up bipole above cis hook w/ tail [26] Down tripole on integral [12] Down tripole below integral [11] Down cis tripole on tripole [26] Down trans tripole on tripole [18]


The 3350 nineteen-bit period 2 pseudo-oscillators

Due to space limitations, these are shown without syntheses on a separate page. All of these can be synthesized using the same techniques that are used for smaller pseudo-oscillators and pseudo-still-lifes, except 4 that involve adding a block to 15-bit period 2 oscillators with no known syntheses. These and ten other syntheses are shown here.

19-bit pseudo-P2

Up bipole under eater w/ cape [22] Down tripole above cis hook w/ tail [42] Up tripole on carrier siamese carrier [13] Block on 15-bit P2 #1 [x+2] Up bipole above carrier siamese eater [15] Block on blinkers bit pole [x+2] Up bipole above long cis hook w/ tail [51]
Up bipole below snake w/ feather [23] Up bipole below carrier w/ feather [21] Block on 15-bit P2 #5 [x+2] Block below 15-bit P2 #5 [x+3] Down beacon on long cis integral [16] Down tripole on cis shillelagh [25] Up tripole above cis hook w/ tail [27]


The 9460 twenty-bit period 2 pseudo-oscillators

Due to space limitations, these are shown without syntheses on a separate page.

All of these can be synthesized using the same techniques that are used for smaller pseudo-oscillators and pseudo-still-lifes, except 25 trivial ones that involve adding a small simple still-life to a large complex period 2 oscillator that does not yet have a synthesis (i.e. 8 with a boat on one of three 15-bit oscillators, and 17 with a block on one of ten 16-bit oscillators). These are not included in the list below.

20-bit pseudo-P2

Up bipole below claw siamese claw w/ cape [26] Up bipole below integral w/ long tail [23] Up bipole on boat w/ cis tail [22] Down tripole below boat w/ very long tail [14] Beacon between up cis snakes [52] Up beacon on very long cis integral [27]
Bipole on snake tie snake [44] Up bipole before long snake siamese eater [11] Up tripole on down loaf w/ tail [11] Down bipole below carrier bridge snake [20] Down tripole below integral w/ down boat [13] Down tripole below integral w/ up boat [14]


The 22134 21-bit period 2 pseudo-oscillators

Due to space limitations, these are shown without syntheses on a separate page.

All of these can be synthesized using the same techniques that are used for smaller pseudo-oscillators and pseudo-still-lifes, except one non-trivial one (shown below) and 169 trivial ones (not shown below) that involve adding a small still-life or oscillator to a large complex period 2 oscillator that does not yet have a synthesis:

Here are syntheses (or lack thereof) for 11 of these. All of the expensive ones were once on the "non-trivial without synthesis" list for a long time, but were eventually solved. Note that these, plus the ones without syntheses, all share three mechanisms that are all very difficult to synthesize: a beacon sandwiched between two other pieces, a bipole with pieces wrapped around it, or a cis python whose free end is near something else.

21-bit pseudo-P2

Beehive on beehive on tripole [10] Beacon between gull w/ two long hooks [178] Beacon between shillelagh and up cis python [88] Up bipole on table on cis python [32] Bipole on carrier behind eater [21] Up snake on up beacon above long hook w/ tail [x]
Up cis python on up beacon below bipole [55] Up cis python on up beacon on bipole [55] Up bipole on feather on hook w/ tail [32] Down bipole on long cis integral [18] Down tripole below carrier bridge snake [18]  


2 22-bit period 2 pseudo-oscillators

22-bit PP2

Boat on beehive on griddle [11] Down tripole on long cis integral [20]


2 23-bit period 2 pseudo-oscillators

23-bit PP2

Tripole below paper clip [10] Beacon between gull w/ two very long hooks [137]


1 24-bit period 2 pseudo-oscillator

24-bit PP2

Cis cis quad-beacon [8]


2 period 2 pseudo-oscillators 26 bits and larger

larger period 2 pseudo-oscillators

Two blocks on spark coil [6] Two beacons on two eaters [10]



3 period 2 pseudo-oscillators buildable from 4 gliders

4gl pseudo-P2

Block on beacon [4] Up boat on beacon [4] Cis block on beacon on block [4]


10 period 2 pseudo-oscillators buildable from 5 gliders

5-glider P2 pseudo-oscillators

Up toad on toad [5] Beehive on beacon [5] Down beacon above eater [5] Up beacon above eater [5] Pond on beacon [5]  
Trans block and up boat on beacon [5] Cis block and up boat on beacon [5] Trans two up boats on beacon [5] Cis two up boats on beacon [5] Cis two up beacons on beacon [5] Cis two beehives on beacon [5]


30 period 2 pseudo-oscillators buildable from 6 gliders

6-glider P2 pseudo-oscillators

Down boat on beacon [6] Down toad on toad [6] Up ship on beacon [6] Up cis beacon on beacon [6] Down ship on beacon [6] Down cis beacon on beacon [6] Up long boat on beacon [6] Up boat on bipole [6] Up loaf on beacon [6] Down loaf on beacon [6]
Down long boat on beacon [6] Up trans beacon on beacon [6] Trans block on beacon on block [6] Down trans beacon on beacon [6] Block on quad- pole [6] Up boat on block on beacon [6] Down boat on block on beacon [6] Cis block and down boat on beacon beacon [6] Beehive on block on beacon [6] Trans block on beacon on beehive [6]
Cis block on up beacon on beacon [6] Up ship on quad- pole [6] Cis block on beacon on beehive [6] Down eater above block on beacon [6] Trans block on beacon above down eater [6] Trans up boat on beacon on beehive [6] Trans block on beacon above up eater [6] Cis up boat on beacon on beehive [6] Two blocks on spark coil [6]  


The 11 period 2 pseudo-oscillators up to 17 bits costing 1 glider/bit

1 glider/bit pseudo-p2

Up bipole on python [15] Down trans python on tripole [16] Up beacon above cis hook w/ tail [16] Down bipole above tub w/ long tail [17] Up boat on extra long hook w/ tail [17] Down tripole above hook w/ tail [17]
Down tripole above shillelagh [17] Down tripole above tub w/ tail [17] Down beacon on extra long hook w/ tail [17] Up beacon behind very long integral [17] Down beacon on very long integral [17]  


The 12 period 2 pseudo-oscillators up to 17 bits costing >1 glider/bit

gt. 1 glider/bit pseudo-p2

Down bipole on hook w/ tail [17] Up bipole on bipole [20] Up bipole below bipole [20] Up bipole above long shil- lelagh [19] Up bipole on long shil- lelagh [21] Down bipole behind long shil- lelagh [23]
Down bipole above long shil- lelagh [18] Down tripole on hook w/ tail [19] Up cis bipole on tripole [24] Up bipole above tub w/ long tail [18] Up bipole behind long shil- lelagh [23] Block on heptapole [18]


The 199 Period-2 pseudo-oscillators up to 21 bits without any known syntheses

All period 2 pseudo-oscillators up to 17 bits have been synthesized. All period 2 pseudo-oscillators up to 21 bits can be synthesized using the same techniques used for smaller pseudo-oscillators and pseudo-still-lifes, except one non-trivial one, and many trivial ones.

There are many trivial pseudo-objects, consisting of a small objects added to a large object that, itself, has eluded synthesis. These include:

The 4 trivial 19-bit ones, and the 1 non-trivial 21-bit ones shown here. (The 25 trivial 20-bit ones and 169 trivial 21-bit ones above are not shown.)

unknown pseudo-P2

Block on 15-bit P2 #1 [x+2] Block on blinkers bit pole [x+2] Block on 15-bit P2 #5 [x+2] Block below 15-bit P2 #5 [x+3] Up snake on up beacon above long hook w/ tail [x]



Related: period-2 oscillators.

Other pseudo-oscillators by period: 2, 3, 4, 5, 6, 8, 10, 12, 15, 30, 60, other.

Other types: still-lifes, pseudo-still-lifes, oscillators, pseudo-oscillators, oscillators by period, pseudo-oscillators by period, guns, multi-colored Life, basic spaceships and pseudo-spaceships, exotic spaceships, spaceships flotillae, puffers, constellations, methuselahs, not quite stable objects.

See also: Life objects sorted by: counts, frequency of occurrence, cost in gliders, name, size in bits, or type.

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Copyright © 1997, 1998, 1999, 2013, 2014 by Mark. D. Niemiec. All rights reserved.
This page was last updated on 2015-02-19.