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 and a stator.
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 glider or spaceship. Strictly speaking "glider" means the little figure so prevalent in Conway's Game of Life, but the more general usage has now become popular.
Important oscillators by period
A list of the firstdiscovered oscillator of each period, as well the current smallestknown oscillator of that period, is provided here. Note that only nontrivial 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 firstdiscovered 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 90degree stable reflector 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


pseudobarberpole

15

6

$rats

David Buckingham

1972


unix

16

7

burloaferimeter

David Buckingham

1972


28P7.1, 28P7.2, 28P7.4, burloaferimeter

28

8

figure eight

Simon Norton

1970


figure eight

12

9

worker bee

David Buckingham

1972


29P9

29

10

42P10.1

David Buckingham

≤1976


24P10

24

11

38P11.1

David Buckingham

1977


rattlesnake

33

12

dinner table

Robert Wainwright

1972


dinner table

33

13

65P13.1

David Buckingham

1976


34P13

34

14

tumbler

George Collins, Jr.

1970


tumbler

16

15

pentadecathlon

John Conway

1970


pentadecathlon

12

16

two preL hasslers

Robert Wainwright

1983


Achim's p16

32

17

54P17.1

Dean Hickerson

1997


Honey thieves

36

18

117P18

David Buckingham

≤1991


43P18

43

19

None found

20

145P20

Noam Elkies

1995


mold on fumarole

30

21

124P21

Robert Wainwright

1995


caterer on 28P7.4

40

22

168P22.1

Noam Elkies

1997


36P22

36

23

None found

24

186P24

Bill Gosper

1994


caterer on figure eight

24

25

134P25

Noam Elkies

1994


p25 honey farm hassler

88

26

prepulsar shuttle 26

David Buckingham

1983


87P26

87

27

123P27.1

Noam Elkies

2002


56P27

56

28

Newshuttle

David Buckingham

1973


prepulsar shuttle 28, mold on 41P7.2, Tnosed p4 on 28P7.4

53

29

prepulsar shuttle 29

David Buckingham

1980


prepulsar shuttle 29

54

30

queen bee shuttle

Bill Gosper

1970


queen bee shuttle

20

31

48P31

Matthias Merzenich

2010


48P31

48

32

gourmet

David Buckingham

1978


gourmet

66

33

258P3 on Achim's p11

Noam Elkies, Achim Flammenkamp

1997


caterer on rattlesnake

46

34

No nontrivial examples found

35

P35 beehive hassler

Dean Hickerson

1995


p35 honey farm hassler

44

36

P36 toad hassler

Robert Wainwright

1984


22P36

22

37

124P37

Nicolay Beluchenko

2009


124P37

124

38

None found

39

134P39.1

David Buckingham, Noam Elkies

2000


caterer on 34P13

46

40

P40 Bheptomino shuttle

David Buckingham

≤1991


26P40

26

41

None found

42

P42 glider shuttle

Noam Elkies

1994


p6 thumb on 28P7.4

55

43

P43 glider loop

Mike Playle

2013


P43 glider loop

228

44

P44 piheptomino hassler

David Buckingham

1992


mold on rattlesnake

45

45

pentadecathlon on snacker

?

≤1995


pentadecathlon on thumb 1

48

46

twin bees shuttle

Bill Gosper

1971


twin bees shuttle

28

47

prepulsar shuttle 47

David Buckingham

1982


prepulsar shuttle 47

84

48

P48 toad hassler

Bill Gosper

1994


unix on Rich's p16

52

49

p49 glider shuttle

Noam Elkies

1999


p49 glider loop

228

50

P50 glider shuttle

Dean Hickerson

1992


P50 traffic jam

92

51

112P51

Nicolay Beluchenko

2009


92P51

92

52

35P52

David Buckingham

1977


35P52

35

53

P53 glider loop

Mike Playle

2013


P53 glider loop

228

54

P54 shuttle

David Buckingham

1974


P54 shuttle

48

55

prepulsar hassler 55

David Buckingham

1986


pseudobarberpole on rattlesnake

49

56

P56 Bheptomino shuttle

David Buckingham

≤1991


P56 Bheptomino shuttle

45

57

P57 Herschel loop 1

Dietrich Leithner

1997


P57 glider loop

228

58

P58 toadsucker

Bill Gosper

1994


prepulsar shuttle 58

104

59

P59 Herschel loop 1

David Buckingham

1997


P59 glider loop

228

60

P60 glider shuttle

David Buckingham

≤ 1971


mold on pentadecathlon

24

61

P61 Herschel loop 1

David Buckingham

1996


P61 glider loop

228

62

?

?

?


110P62

110

63

?

?

?


snacker on 38P7.2

78

64

?

?

?


Merzenich's p64

34

65

?

?

?


fumarole on 34P13

52

66

?

?

?


caterer on 36P22

48

67

?

?

?


?

?

68

?

?

?


?

?

69

?

?

?


?

?

70

?

?

?


78P70

78

71

?

?

?


?

?

72

47P72

Robert Wainwright

1990


figure eight on 22P36

36

73

?

?

?


?

?

74

?

?

?


?

?

75

?

?

?


6 bits

49

76

?

?

?


?

?

77

?

?

?


77P77

77

78

?

?

?


p6 thumb on 34P13

61

79

?

?

?


?

?

80

?

?

?


fumarole on Rich's p16

52

81

?

?

?


?

?

82

?

?

?


?

?

83

?

?

?


?

?

84

?

?

?


52P84

52

85

?

?

?


?

?

86

?

?

?


?

?

87

?

?

?


84P87

84

88

P88 piheptomino hassler

Dean Hickerson

1994


figure eight on rattlesnake

45

89

?

?

?


?

?

90

?

?

?


fumarole on 43P18

61

91

?

?

?


?

?

92

?

?

?


twin bees shuttle on 22P4.3

50

93

?

?

?


caterer on 48P31

60

94

?

?

?


?

?

95

?

?

?


?

?

96

?

?

?


caterer on 68P32

80

97

?

?

?


?

?

98

?

?

?


?

?

99

?

?

?


?

?

100

Centinal

Bill Gosper

≤1987


centinal

70

104

?

?

?


figure eight on 34P13

46

105

?

?

?


pentadecathlon on 37P7.1

49

108

?

?

?


22P4.3 on 56P27

78

110

P110 traffic jam

Bill Gosper

1994


pseudobarberpole on 36P22

51

120

?

?

?


figure eight on pentadecathlon

24

124

P124 lumps of muck hassler

Dean Hickerson

1994


mold on 48P31

60

132

P132 piheptomino hassler

David Buckingham

≤1994


?

?

135

106P135

Bill Gosper

1989


pentadecathlon on 56P27

68

138

?

?

?


Gabriel's p138

36

144

Achim's p144

Achim Flammenkamp

1994


Achim's p144

42

156

P156 Hans Leo hassler

Noam Elkies

1995


92P156

92

177

?

?

?


104P177

104

200

P200 traffic jam

Bill Gosper

1994


figure eight on centinal

82

312

periodtripled p104 gun

Dave Greene

2004


60P312

60

See also
External links