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2007 January 30

Glider Constructions
Natural Clock

17.101-L-7 My ongoing project of going through collisions of a Glider with 16 and 17 bit stable objects looking for those that might be useful in object construction has found something else interesting. For the first time, I've come across a methuselah pattern that generates a natural, non-trivial Clock. The starting pattern is a Glider colliding with a 17-bit object. The Clock appears at generation 864, while the pattern finally settles down at 1507 generations

In the past, some of my large random pattern surveys turned up the occasional Clock, but whenever I looked closely at them, all that were examined showed that the Clock formed in the first generation or two and then somehow managed to survive all the turmoil of the next few thousand generations. I don't remember ever seeing one that appeared midway or late in a pattern's evolution.

Clock ConstructionJason Summers took one of the predecessor generations and was able to produce a six-Glider construction which cleanly builds a Clock in 52 generations.

Clock ConstructionClocks can be constructed with as few as four Gliders, and a few constructions from other objects are also known.

2005 July 14

Methuselahs
New Record Methuselah

Andrzej Okrasinski has found a new methuselah record holder, a 15 bit intial pattern with a final population of 1623 after 29053 generations. David Bell quickly found a 13 cell predecessor, bringing the record to 29055.

Some of the more unusual objects which make an appearance but which aren't in the final census include a Lightweight Spaceship [9P4H2V0.1], a Fishook Eater [7.3], a Long Barge [8.9], a Big S [14.492], a Bi-Pond [16.2630] and an unnamed 13 bit object [13.182].

Size Discoverer Gens Final Pop. Final Pattern, Census
13 13 Bit Methuselah
[David Bell]
29055 1623 15 Bit Methuselah
102(4.1), 2(4.2), 15(5.1), 6(6.2), 57(6.4), 1(7.2), 18(7.4), 5(8.7), 2(12.41), 135(3P2.1), 1(6P2.1), 1(6P2.2), 28(5P4H1V1.1)
15 15 Bit Methuselah
[Andrzej Okrasinski]
29053

Note: Not all of the paths of escaped gliders are shown.

2005 February 21

Methuselahs
New Methuselah Records

Tomas Rokicki has announced some of the results of a survey for methuselahs. The table below shows the record holding patterns for given bit sizes. More information can be found at his webpage. Other information about methuselahs, can be found at Dean Hickerson's website. Andrzej Okrasinski also announced his finding of the current record holding pattern.

Size Name Gens Final Pop. Final Pattern, Census & Discoverer
r pentomino
r Pentomino
1103 128 r pentomino
8(4.1), 1(5.1), 1(6.2), 4(6.4), 1(7.4), 4(3P2.1), 6(5P4H1V1.1)
5 r pentomino 1105
6 r pentomino 1108
7 Acorn
Acorn

[Charles Corderman]
5206 633 Acorn
34(4.1), 8(5.1), 3(6.2), 30(6.4), 2(6.5), 5(7.4), 2(8.7), 1(8.8), 41(3P2.1), 13(5P4H1V1.1)
8 New Methuselah
[Tomas Rokicki]
7467 952 New Methuselah
51(4.1), 2(4.2), 11(5.1), 4(6.2), 35(6.4), 16(7.4), 2(8.7), 1(14.475), 61(3P2.1), 1(6P2.1), 24(5P4H1V1.1)
Bunnies
Rabbits

[Andrew Trevorrow]
17331 1749 Bunnies
109(4.1), 4(4.2), 18(5.1), 7(6.2), 65(6.4), 18(7.4), 3(8.7), 136(3P2.1), 2(6P2.1), 40(5P4H1V1.1)
9 Bunnies9
[Paul Callahan]
17410
10 Bunnies0
[Tomas Rokicki]
17423
11 Bunnies11
[Tomas Rokicki]
17465
12-18 New Methuselah
[Tomas Rokicki]
23334 2898 New Methuselah
207(4.1), 7(4.2), 23(5.1), 12(6.2), 115(6.4), 2(7.2), 32(7.4), 4(8.7), 171(3P2.1), 1(6P2.1), 2(6P2.2), 70(5P4H1V1.1), 1(9P4H2V0.1)
19 New Methuselah
[Andrzej Okrasinski]
28786 3091 New Methuselah
196(4.1), 6(4.2), 31(5.1), 9(6.2), 143(6.4), 3(6.5), 34(7.4), 6(8.7), 2(12.41), 1(14.475), 213(3P2.1), 47(5P4H1V1.1)

Note: Not all of the paths of escaped gliders are shown.