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Revision as of 02:06, 29 May 2022
An oscillator is a pattern that is a predecessor of itself. That is, it is a pattern that repeats itself after a fixed number of generations (known as its period). The term is usually restricted to finite patterns that are not still lifes, though still lifes may be thought of as oscillators with period 1. An oscillator is divided into a rotor (the individual cells that actually oscillate) and a stator (the cells which remain alive throughout its whole period).
Cellular automaton theory recognizes shift periodicity, which refers to a configuration reappearing in shifted form after a lapse of one or more generations. Without the shift, it is an oscillator, but if it moves it would be called a spaceship.
Important oscillators by period
A list of the first-discovered oscillator of each period,[1] as well the current smallest-known oscillator of that period,[2] is provided here. Note that only non-trivial oscillators are considered here, in the sense that there must be at least one cell that oscillates at the full period. In some cases, it is not known for certain what the first-discovered oscillator of a given period is, and in such situations all possible candidates are listed. For any period 61 or greater an oscillator can be constructed using the Herschel track method. In April, 2013 Mike Playle found a small 90-degree stable reflector known as the Snark that allows oscillators of all periods 43 or greater to be constructed.
| Period
|
First discovered
|
Discoverer
|
Year of discovery
|
|
Smallest known
|
Minimum # of cells
|
| 2
|
blinker
|
John Conway
|
1970
|
blinker
|
3
|
| 3
|
pulsar
|
John Conway
|
1970
|
caterer
|
12
|
| 4
|
pinwheel
|
Simon Norton
|
1970
|
mazing, mold
|
12
|
| 5
|
octagon 2
|
Sol Goodman, Arthur Taber
|
1971
|
pseudo-barberpole
|
15
|
| 6
|
$rats
|
David Buckingham
|
1972
|
unix
|
16
|
| 7
|
burloaferimeter
|
David Buckingham
|
1972
|
28P7.1, 28P7.2, 28P7.3, burloaferimeter
|
28
|
| 8
|
figure eight
|
Simon Norton
|
1970
|
figure eight
|
12
|
| 9
|
worker bee
|
David Buckingham
|
1972
|
29P9
|
29
|
| 10
|
42P10.3
|
David Buckingham
|
≤1976
|
24P10
|
24
|
| 11
|
38P11.1
|
David Buckingham
|
1977
|
rattlesnake
|
33
|
| 12
|
dinner table
|
Robert Wainwright
|
1972
|
dinner table
|
33
|
| 13
|
Buckingham's p13
|
David Buckingham
|
1976
|
Beluchenko's p13
|
34
|
| 14
|
tumbler
|
George Collins
|
1970
|
tumbler
|
16
|
| 15
|
pentadecathlon
|
John Conway
|
1970
|
pentadecathlon
|
12
|
| 16
|
two pre-L hasslers
|
Robert Wainwright
|
1983
|
Rob's p16
|
21
|
| 17
|
54P17.1
|
Dean Hickerson
|
1997
|
honey thieves
|
36
|
| 18
|
117P18[note 1]
|
David Buckingham
|
≤1991
|
p18 bi-block hassler, p18 phase shifter
|
43
|
| 19
|
None found
|
| 20
|
145P20[note 1]
|
Noam Elkies
|
1995
|
mold on fumarole
|
30
|
| 21
|
124P21[note 1]
|
Robert Wainwright
|
1995
|
32P21
|
32
|
| 22
|
168P22.1
|
Noam Elkies
|
1997
|
Jason's p22
|
36
|
| 23
|
David Hilbert
|
Luka Okanishi, praosylen
|
2019
|
p23 honey farm hassler
|
76
|
| 24
|
186P24[note 1]
|
Bill Gosper
|
1994
|
caterer on figure eight
|
24
|
| 25
|
134P25
|
Noam Elkies
|
1994
|
30P25
|
30
|
| 26
|
p26 pre-pulsar shuttle
|
David Buckingham
|
1983
|
87P26
|
87
|
| 27
|
123P27.1
|
Noam Elkies
|
2002
|
56P27
|
56
|
| 28
|
newshuttle
|
David Buckingham
|
1973
|
mold on 34P14 shuttle
|
46
|
| 29
|
p29 pre-pulsar shuttle
|
David Buckingham
|
1980
|
p29 pre-pulsar shuttle
|
54
|
| 30
|
queen bee shuttle
|
Bill Gosper
|
1970
|
queen bee shuttle
|
20
|
| 31
|
Merzenich's p31
|
Matthias Merzenich
|
2010
|
Merzenich's p31
|
48
|
| 32
|
gourmet
|
David Buckingham
|
1978
|
p32 honey farm hassler
|
45
|
| 33
|
258P3 on Achim's p11
|
Noam Elkies, Achim Flammenkamp
|
1997
|
caterer on rattlesnake
|
46
|
| 34
|
No non-trivial examples found
|
| 35
|
p35 beehive hassler[note 1]
|
Dean Hickerson
|
1995
|
p35 honey farm hassler
|
44
|
| 36
|
p36 toad hassler[note 1]
|
Robert Wainwright
|
1984
|
22P36
|
22
|
| 37
|
Beluchenko's p37
|
Nicolay Beluchenko
|
2009
|
Beluchenko's p37
|
124
|
| 38
|
44P38
|
David Raucci
|
2022
|
44P38
|
44
|
| 39
|
134P39.1
|
David Buckingham, Noam Elkies
|
2000
|
caterer on Beluchenko's p13
|
46
|
| 40
|
p40 B-heptomino shuttle[note 1]
|
David Buckingham
|
1991
|
Beluchenko's p40
|
26
|
| 41
|
None found
|
| 42
|
p42 glider shuttle[note 1]
|
Noam Elkies
|
1994
|
unix on 34P14 shuttle
|
50
|
| 43
|
p43 Snark loop
|
Mike Playle
|
2013
|
p43 Snark loop
|
228
|
| 44
|
p44 pi-heptomino hassler
|
David Buckingham
|
1992
|
mold on rattlesnake
|
45
|
| 45
|
pentadecathlon on snacker
|
Mark Niemiec, John Conway
|
≤1995
|
pentadecathlon on thumb 1
|
48
|
| 46
|
twin bees shuttle
|
Bill Gosper
|
1971
|
twin bees shuttle
|
28
|
| 47
|
p47 pre-pulsar shuttle
|
David Buckingham
|
1982
|
p47 pre-pulsar shuttle
|
84
|
| 48
|
p48 toad hassler
|
Bill Gosper
|
1994
|
30P3 on Rob's p16
|
51
|
| 49
|
p49 glider shuttle
|
Noam Elkies
|
1999
|
p49 bumper loop
|
206
|
| 50
|
p50 glider shuttle
|
Dean Hickerson
|
1992
|
24P10 on 30P25
|
58
|
| 51
|
Beluchenko's p51
|
Nicolay Beluchenko
|
2009
|
90P51
|
90
|
| 52
|
Four eaters hassling lumps of muck
|
David Buckingham
|
1977
|
four eaters hassling lumps of muck
|
35
|
| 53
|
p53 Snark loop
|
Mike Playle
|
2013
|
p53 Snark loop
|
228
|
| 54
|
p54 shuttle
|
David Buckingham
|
1973
|
p54 shuttle
|
48
|
| 55
|
p55 pre-pulsar hassler
|
David Buckingham
|
1986
|
pseudo-barberpole on rattlesnake
|
49
|
| 56
|
p56 B-heptomino shuttle[note 1]
|
David Buckingham
|
≤1991
|
p56 B-heptomino shuttle
|
45
|
| 57
|
p57 Herschel loop 1
|
Dietrich Leithner
|
1997
|
p57 180° glider loop
|
146
|
| 58
|
p58 toadsucker
|
Bill Gosper
|
1994
|
p58 pre-pulsar shuttle
|
104
|
| 59
|
p59 Herschel loop 1
|
David Buckingham
|
1997
|
p59 Snark loop
|
228
|
| 60
|
p60 glider shuttle
|
David Buckingham
|
≤ 1971
|
mold on pentadecathlon
|
24
|
| 61
|
p61 Herschel loop 1
|
David Buckingham
|
1996
|
p61 Snark loop
|
228
|
| 62
|
?
|
?
|
?
|
66P62
|
66
|
| 63
|
?
|
?
|
?
|
meatball on p9 thumb
|
74
|
| 64
|
?
|
?
|
?
|
Merzenich's p64
|
34
|
| 65
|
?
|
?
|
?
|
fumarole on Beluchenko's p13
|
52
|
| 66
|
?
|
?
|
?
|
caterer on Jason's p22
|
48
|
| 67
|
?
|
?
|
?
|
p67 Snark loop
|
228
|
| 68
|
?
|
?
|
?
|
72P68
|
72
|
| 69
|
?
|
?
|
?
|
p69 180° glider loop
|
146
|
| 70
|
?
|
?
|
?
|
fumarole on 34P14 shuttle
|
52
|
| 71
|
?
|
?
|
?
|
p71 Snark loop
|
228
|
| 72
|
two blockers hassling R-pentomino
|
Robert Wainwright
|
1990
|
figure eight on 22P36
|
36
|
| 73
|
?
|
?
|
?
|
p73 Snark loop
|
228
|
| 74
|
p74 Herschel loop
|
David Buckingham
|
1996
|
Raucci's p74
|
84
|
| 75
|
6 bits
|
Robert Wainwright
|
1984
|
pentadecathlon on 30P25
|
46
|
| 76
|
?
|
?
|
?
|
mold on 44P38
|
56
|
| 77
|
?
|
?
|
?
|
meatball on rattlesnake
|
71
|
| 78
|
?
|
?
|
?
|
p6 thumb on Beluchenko's p13
|
61
|
| 79
|
?
|
?
|
?
|
p79 Snark loop
|
228
|
| 80
|
?
|
?
|
?
|
fumarole on Rob's p16
|
39
|
| 81
|
?
|
?
|
?
|
p81 180° glider loop
|
146
|
| 82
|
?
|
?
|
?
|
p82 Snark loop
|
208
|
| 83
|
?
|
?
|
?
|
p83 Snark loop
|
228
|
| 84
|
?
|
?
|
?
|
p84 honey farm hassler
|
42
|
| 85
|
?
|
?
|
?
|
74P85
|
74
|
| 86
|
?
|
?
|
?
|
p86 Snark loop
|
208
|
| 87
|
?
|
?
|
?
|
84P87
|
84
|
| 88
|
p88 glider loop
|
David Buckingham
|
1992
|
figure eight on rattlesnake
|
45
|
| 89
|
?
|
?
|
?
|
p89 Snark loop
|
228
|
| 90
|
?
|
?
|
?
|
thumb 1 on queen bee shuttle
|
56
|
| 91
|
?
|
?
|
?
|
meatball on Beluchenko's p13
|
72
|
| 92
|
?
|
?
|
?
|
twin bees shuttle on 21P4.1
|
49
|
| 93
|
?
|
?
|
?
|
caterer on Merzenich's p31
|
60
|
| 94
|
capped AK-47 gun
|
Dean Hickerson
|
1990
|
capped AK-94
|
110
|
| 95
|
?
|
?
|
?
|
p95 180° glider loop
|
166
|
| 96
|
?
|
?
|
?
|
period-48 glider gun with boat-bit
|
59
|
| 97
|
?
|
?
|
?
|
p97 Snark loop
|
228
|
| 98
|
?
|
?
|
?
|
Gallus
|
105
|
| 99
|
?
|
?
|
?
|
48P9 on rattlesnake
|
82
|
| 100
|
centinal
|
Bill Gosper
|
≤1987
|
mold on 30P25
|
42
|
| 101
|
?
|
?
|
?
|
p101 Snark loop
|
228
|
| 102
|
?
|
?
|
?
|
Raucci's p102
|
67
|
| 103
|
?
|
?
|
?
|
p103 Snark loop
|
228
|
| 104
|
?
|
?
|
?
|
figure eight on Beluchenko's p13
|
46
|
| 105
|
?
|
?
|
?
|
pentadecathlon on 37P7.1
|
49
|
| 106
|
?
|
?
|
?
|
p106 rectifier loop
|
169
|
| 107
|
?
|
?
|
?
|
p107 rectifier loop
|
136
|
| 108
|
?
|
?
|
?
|
22P4.3 on 56P27
|
78
|
| 109
|
?
|
?
|
?
|
p109 rectifier loop
|
156
|
| 110
|
p110 traffic jam
|
Bill Gosper
|
1994
|
pseudo-barberpole on Jason's p22
|
51
|
| 111
|
?
|
?
|
?
|
p111 rectifier loop
|
136
|
| 112
|
?
|
?
|
?
|
tumbler on Rich's p16
|
50
|
| 113
|
?
|
?
|
?
|
nihonium
|
106
|
| 114
|
?
|
?
|
?
|
caterer on 44P38
|
57
|
| 115
|
?
|
?
|
?
|
p115 rectifier loop
|
136
|
| 116
|
?
|
?
|
?
|
102P116
|
102
|
| 117
|
?
|
?
|
?
|
112P117
|
112
|
| 118
|
?
|
?
|
?
|
p118 rectifier loop
|
154
|
| 119
|
?
|
?
|
?
|
p119 rectifier loop
|
136
|
| 120
|
?
|
?
|
?
|
figure eight on pentadecathlon
|
24
|
| 124
|
p124 lumps of muck hassler
|
Dean Hickerson
|
1994
|
mold on Merzenich's p31
|
60
|
| 126
|
?
|
?
|
?
|
snacker on 34P14 shuttle
|
74
|
| 128
|
?
|
?
|
?
|
p128 wing shuttle, p128 Coe-blocker loop
|
108
|
| 129
|
?
|
?
|
?
|
p129 180° glider loop
|
146
|
| 130
|
?
|
?
|
?
|
55P10 on Beluchenko's p13
|
89
|
| 132
|
p132 glider loop
|
David Buckingham
|
1992
|
mold on Jason's p33
|
72
|
| 135
|
106P135
|
Bill Gosper
|
1989
|
pentadecathlon on 56P27
|
68
|
| 136
|
?
|
?
|
?
|
p136 Coe-blocker loop
|
108
|
| 138
|
?
|
?
|
?
|
Gabriel's p138
|
36
|
| 140
|
p140 traffic jam
|
Bill Gosper
|
1994
|
34P14 shuttle on dockyard
|
82
|
| 141
|
?
|
?
|
?
|
p47 pre-pulsar shuttle phase-shifting 28P7.1
|
114
|
| 143
|
?
|
?
|
?
|
p143 Bandersnatch loop
|
144
|
| 144
|
capped p144 gunstar
|
David Buckingham
|
1990
|
Achim's p144
|
42
|
| 150
|
?
|
?
|
?
|
unix on 30P25
|
46
|
| 152
|
?
|
?
|
?
|
figure eight on 44P38
|
60
|
| 156
|
p156 traffic jam oscillator
|
Bill Gosper
|
1994
|
p156 unix loop
|
86
|
| 165
|
?
|
?
|
?
|
rattlesnake on pentadecathlon
|
45
|
| 168
|
?
|
?
|
?
|
figure eight on 32P21
|
44
|
| 177
|
?
|
?
|
?
|
Karel's p177
|
104
|
| 184
|
?
|
?
|
?
|
figure eight on twin bees shuttle
|
40
|
| 186
|
?
|
?
|
?
|
unix on Merzenich's p31
|
64
|
| 188
|
?
|
?
|
?
|
AK-94 with boat-bits
|
108
|
| 196
|
?
|
?
|
?
|
p196 pi-heptomino hassler
|
66
|
| 200
|
p200 glider loop
|
Bill Gosper
|
≤1987
|
figure eight on 30P25
|
42
|
| 226
|
?
|
?
|
?
|
nihonium*
|
107
|
| 230
|
?
|
?
|
?
|
fumarole on twin bees shuttle
|
46
|
| 231
|
?
|
?
|
?
|
rattlesnake on 32P21
|
66
|
| 232
|
?
|
?
|
?
|
figure eight on p29 pre-pulsar shuttle
|
66
|
| 240
|
?
|
?
|
?
|
pentadecathlon on Rob's p16
|
33
|
| 246
|
?
|
?
|
?
|
period-246 glider gun variant
|
68
|
| 256
|
?
|
?
|
?
|
p256 Coe-blocker loop
|
103
|
| 276
|
?
|
?
|
?
|
caterer on 50P92.1
|
62
|
| 300
|
?
|
?
|
?
|
pentadecathlon on centinal
|
88
|
| 312
|
?
|
?
|
?
|
60P312
|
60
|
| 320
|
?
|
?
|
?
|
fumarole on Merzenich's p64
|
52
|
| 360
|
?
|
?
|
?
|
thumb 1 on Beluchenko's p40
|
62
|
| 368
|
?
|
?
|
?
|
period-184 glider gun with boat-bits
|
50
|
| 460
|
?
|
?
|
?
|
pseudo-barberpole on 50P92.1
|
65
|
| 492
|
?
|
?
|
?
|
period-246 glider gun with boat-bit
|
87
|
| 496
|
?
|
?
|
?
|
Rob's p16 on Merzenich's p31
|
69
|
| 512
|
?
|
?
|
?
|
period-256 glider gun with boat-bits
|
100
|
| 856
|
period-856 glider gun
|
David Buckingham
|
1991
|
p856 Coe-blocker loop
|
103
|
Flipper
A flipper is any oscillator that forms its mirror image halfway through its period. For example, see p60 toad flipper.
Notes
References
See also
External links
Forum threads