View source for Conway's Game of Life: Mathematics and Construction/Errata

This page is intended to catalogue any anachronisms or typos found in the book [[Conway's Game of Life: Mathematics and Construction]].

== Anachronisms ==

The book is up-to-date as of January 15, 2022. The discoveries listed here are all from after that date.

{| class="sortable wikitable"
|-
! Date
! Section
! Pages
! Notes
|-
| January 29, 2022
| 8.5
| 234
| Table 8.1 does not include the period-27 glider gun [https://conwaylife.com/forums/viewtopic.php?p=140915#p140915 found by goldenratio and hotdogPi].
|-
| February 14, 2022
| 8.5
| 236
| [https://conwaylife.com/forums/viewtopic.php?p=141620#p141620 JP21 found a new (smaller) p28 gun], making the sentence "The only known true-period 28 glider gun is also based on hassling a T-tetromino..." no longer true.
|-
| April 12, 2022
| 8.5.1
| 233-4
| iNoMed and David Raucci have assembled a [https://conwaylife.com/forums/viewtopic.php?p=144139#p14413 single-engine p36 gun]. Nothing in the book is technically incorrect, but "36" is now a slight anachronism in the section title "Spark Collisions: True-Period 22, 30, 33, 36, 45, and 46 Guns"
|-
| June 25, 2022
| 8.5.2
| 234-6
| iNoMed and cvojan have built [https://conwaylife.com/forums/viewtopic.php?p=147512#p147512 guns based on a new p37 R-hassling oscillator], which is not in the table. "37" should now be included in the 8.5.2 section title.
|-
| July 6, 2022
| 3.7
| 73
| "34" can be removed from the list of unknown periods.
|-
| November 2, 2022
| Exercise 8.17
| 265
| Period 51 now has a very simple [https://conwaylife.com/forums/viewtopic.php?p=153007#p153007 honeyfarm hassler gun] as well as the larger one based on the hotcrystal0 reaction. Nothing in the book seems to be inaccurate, but possibly a reference to the smaller p51 could be added in the footnote.
|-
| November 8, 2022
| 8.5.2
| 234-6
| "25" can be added to the table due to [https://conwaylife.com/forums/viewtopic.php?p=153265#p153265 this p25 gun]. It's a "modified B-heptomino hassler", so it '''could''' be added to the hasslers section, but maybe that object isn't common enough to count as "common".
|-
| April 5, 2023 (p61 glider gun) and/or July 24, 2022 (speed tunnel)
| 8.5.2
| 234-6
| "61" can be added to the hasslers section due to [[Period-61 glider gun (2023)|this p61 gun]]. But also the p61 and p62 lines could simply be cut from the table, and explanatory text could say that all periods 61 and above can be achieved with [[speed tunnel]]s and a carefully chosen subset of Herschel tracks.
|-
| July 14, 2023
| 3.7
| 73
| "19" and "41" can be removed from the list of unknown periods (which can be made empty); 2023 can be added as a year in which new periods were discovered, and Life was proven omniperiodic.
|}

== Errata and Typos ==

{| class="sortable wikitable"
|-
! Section
! Pages
! Notes
|-
| 4.5.2
| 103
| ''When this happens, the wire is instead called a wick, and the '''objects''' that '''“burns”''' through the wick is called a fuse.'' Subject-verb disagreement.
|-
| 6
| 154
| "... typically smaller and simpler that stationary circuitry ..." should be "... typically smaller and simpler than stable circuitry ..."
|-
| 6.3.3
| 168
| In footnote 17, "stationary" should be "stable" instead.
|-
| 6.6
| 181
| There appears to be an erroneous space between problem 6.31 and its asterisk.
|-
| 7.9
| 211
| Footnote 40 appears on page 212, though the reference is on page 211.
|-
| 7.9
| 218
| There appears to be an erroneous space between problem 7.38 and its asterisk.
|-
| 7.9
| 218
| In problem 7.38, "true period" should be "true-period" as it is throughout the book.
|-
| 9.8, Figure 9.17
| 307
| (FIXED 04/23/2022 on website and PDF) Omission - the pattern file [https://conwaylife.com/book/patterns/universal_computation/osqrtlogt.txt reachable by clicking Figure 9.17] has comments that imply that the pattern is Adam P. Goucher's original Osqrtlogt. An additional line should say "Partially rebuilt and reduced by Dave Greene and Nathaniel Johnston in 2019-20, using newer components like [[Snark]] and [[syringe]]."
|-
| 10.2.1
| 322
| Typo - "behind a backward ra'''t'''e" should be "behind a backward ra'''k'''e"
|-
| 11.7.3, Figure 11.24
| 375
| Typo - "... allowing the crab two carry two construction ..." first instance of "two" should be "to".
|-
| 11.7.3, Figure 11.24
| 375
| Typo - "... so as trigger the ignitions." should be "... so as to trigger the ignitions."
|-
| 11.27
| 380
| Typo - "bounces around the diamond-shaped track highlighted '''track''' in orange":  second instance of "track" should be removed.
|-
| 12.3
| 395
| Figure 12.16 caption, "degrees). Uses the same state" → "degrees). '''It''' uses the same state"
|-
| Pattern Library
| 
| The pattern file for Chapter 4 exercise 4.28 in the library is named "beehive wire" but should be "beehive wick" (the rle file contains the correct name).
|}

== Technically Correct, but Misleading ==

{| class="sortable wikitable"
|-
! Section
! Pages
! Notes
|-
| 4.6.2
| 110
| The text says that the adjustable bi-block rake of Figure 4.52 can have its period increased by 32 by adding additional bi-blocks. It should be noted that its period can also be increased by 8 by moving the front pair of rakes forward by 2 generations.
|-
| 5.8
| 147
| The text says that a 17-glider RCT mechanism was found in September 2020.  That's true enough, but now it should probably say instead that a 16-glider mechanism was found in April 2022.
|-
| 6.4
| 171
| The p34 oscillator discovered in July 2022 has an optional attachment that allows a bumper mechanism to [https://discord.com/channels/357922255553953794/370571014654001154/994182431441686578 work at the minimum possible period].
|}

[[Category:Books and articles]]