# Talk:Rule 90

See Talk:Rule 30#Suggested name change--RDBury (talk) 16:19, 15 May 2009 (UTC)

Stephen Wolfram made a comment on Rule 90 saying that it will reproduce the first line after some iterations. 
Now any automata on a finite grid must necessarily repeat itself sooner or later, since there's only limited number of configurations. The same is true for random number generators or the ducci sequences. 
But only some automata would reproduce any starting configuration, the rest may be caught in loops that do not include that specific configuration. Is this a noteworthy "interesting property" of Rule 90 or some larger class of rules? 
EverGreg (talk) 19:35, 3 September 2010 (UTC)

Uhm wait.. The sierpinski triangle is a counter-example, isn't it? the starting configuration never re-appears. EverGreg (talk) 19:43, 3 September 2010 (UTC)
For any finite pattern it eventually produces two copies of that pattern, that's probably what he meant by reproduce. Dmcq (talk) 21:06, 3 September 2010 (UTC)

This review is transcluded from Talk:Rule 90/GA1. The edit link for this section can be used to add comments to the review.
Reviewer: CheCheDaWaff (talk · contribs) 21:11, 19 October 2016 (UTC)

I'm planning to review this article. It should be done soon: today or tomorrow. --♫CheChe♫ talk 21:11, 19 October 2016 (UTC)


### Summary
The article is very close to meeting the Good Article Criteria. If the relatively minor issues with the writing can be resolved then I would be happy to give this article a pass. As it stands I'm putting the article on hold, pending response to my review.
That being said I have a few suggestions that fall outside the Good Article Criteria (and thus cannot be used for approval either way).

Consider using 'Highlife replicator.svg' in place of 'Highlife replicator.png'
Consider adding alt text to images
Consider mentioning some more applications (if there are any)


### Breakdown
Writing

Prose is generally good, but is prone to overly long, confusing sentences. For example, I found this sentence in 'Emulation by other systems' difficult to read: For instance, a configuration in rule 90 may be translated into a configuration into the different elementary cellular automaton Rule 22 by replacing each Rule 90 cell by three consecutive Rule 22 cells that are either all zero (if the Rule 90 cell is itself zero) or a one followed by two zeros (if the Rule 90 cell is a one). This should be broken up into smaller sentences if possible. In general it would be worth going through the article and similarly trying to break up unwieldy sentences as long as doing so doesn't sacrifice meaning.
I would suggest the following specific copy edits.

In 'Emulations by other systems' second paragraph I would write:
Various other cellular automata are known to support replicators, patterns that make copies of themselves, with the same behavior as in the tree growth model for Rule 90. A new copy is placed to either side of the replicator pattern as long as the space there is empty, but if two replicators both attempt to copy themselves into the same position, then the space remains blank, and in either case the replicators themselves vanish, leaving their copies to carry on the replication.
The original sentence was extremely long. I've removed the colon (replacing it with a full stop) because both clauses where complete sentences and it didn't provide any extra meaning. I also removed an unnecessary and confusing comma after 'replicator pattern'.
The colon in the first sentence of 'Predecessors and Gardens of Eden' is between two complete sentences and provides no extra meaning. I would suggest replacing it with a full stop or a semi-colon.

Compliance with manual of style:

Lead section has some room for improvement. In particular, it isn't obvious to an uninitiated reader that this is a topic in mathematics / simulation.
✓ Layout.
✓ Words to watch.
(N/A) Fiction.
(N/A) List incorporation.

Verifiability & Original Research

✓ All references presented in appropriate layout.
✓ Sources are reliable.
✓ Likely-to-be-challenged information is cited.
(N/A) Statistics cited.
✓ No original research.
✓ No copyright violations / plagiarism.

Topic Coverage

✓ Addresses main aspects of topic.
✓ Stays focused.

Neutral point of view ✓
Stable ✓
Illustrations

✓ Images present if possible.
✓ Correct copyright tags.
✓ Images relevant.
✓ Captions appropriate.

Previous review issues adequately addressed (if applicable). (N/A)
No technical issues. ✓
--♫CheChe♫ talk 00:21, 20 October 2016 (UTC)

@CheCheDaWaff: Thanks for the review! I disagree that the colons were meaningless. They were intended to mean that the second independent clause provides an explanation for the first clause; otherwise, I would have used a semicolon or dash. Regardless, I have expanded the lead to better represent the whole article, made a copyediting pass over the whole article, and broken up several long sentences. —David Eppstein (talk) 01:23, 23 October 2016 (UTC)
@David Eppstein: Wonderful! The article is much improved now that it's less of a struggle to understand. The new lead is very nice as well. I've got no problem passing this now. Well done!   --♫CheChe♫ talk 08:28, 23 October 2016 (UTC)

Where does the name "bowtie pasta" for the HighLife replicator come from? I've never seen it used before.  — Preceding unsigned comment added by EZ132 (talk • contribs) 23:58, 25 November 2020 (UTC) 

That name is used (with the slightly different spelling "bow tie pasta") by Evans, K. M. (2003), "Replicators and Larger-than-Life examples", New constructions in cellular automata. Evans might have invented the name; it doesn't seem to be widespread beyond that publication. —David Eppstein (talk) 00:11, 26 November 2020 (UTC)