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2020-07-11 22:12 nesdori  
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and here we go again: guess what? 5! the standard rng and seed like always.  
  
this time the puzzle is something very different. you need knowledge out of the scope of boulder dash. but that's life.. :)

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2020-07-11 22:36 nesdori  
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if you know the answer, please reply "i got it!" instead of telling the answer. it would be interesting to see how many "i got it"'s there will be.. :)

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2020-07-11 23:01 Arno  
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i got it! :-)

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2020-07-11 23:36 nesdori  
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 Arno , i knew that you'll be one saying that :D a bonus point if you know where's a flying formation.. :)

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2020-07-12 00:32 dustin  
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unsolvable to me - i don't have any knowledge beyond the scope of boulder dash :p ;d

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2020-07-12 00:46 nesdori  
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 dustin , oh! that's quite surprising because you are both mathematician and fond of different games.. :)

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2020-07-12 10:28 Arno  
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yes a 'glider' can be found at the left side of the middle floor. it moves south-east! :-D

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2020-07-12 10:47 nesdori  
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 Arno , correct! it was quite funny that a glider happened to be formed :) now there's another hint. let's see if there'll be more "i gots" now before i reveal the answer.

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2020-07-12 11:48 Arno  
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thx! i also found that the formation to the right of it would be a 'still life' if that diamond were a boulder! :-)  
  
hope i haven't given too much hints now...! ;-D

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2020-07-12 11:55 DarkStoorM  
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Ah, I should read the first comment again, then I'd get what was the reference :D  
  
I found three patterns :D top-left is a nice explosion

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2020-07-12 13:03 dustin  
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ahhh, wait a moment! no more hints! ;d

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2020-07-12 13:11 dustin  
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i got it!

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2020-07-12 14:06 nesdori  
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 dustin , so you really didn't read the hint at first. i told you that it's not wise thing to do this time ;)

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2020-07-12 14:22 dustin  
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 nesdori , yes i did read it, but it wasn't enough. it was only after  Arno 's bonus point that i realized what's going on ;d

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2020-07-12 16:04 nesdori  
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the correct answer is that "conway's game of life" ( <a href="https://en.wikipedia.org/wiki/Conway%27s_Game_of_Life" target="external">https://en.wikipedia.org/wiki/Conway%27s_Game_of_Life</a> ) transition rules are applied once to the original cave layout. this time the hint was quite straightforward :) the game of life is pretty well-known, at least by name and approximate rules, and especially among retro gamers, so i expected to see more than one answer this time :)  
  
the rules are simple:  
  
- any live cell with fewer than two live neighbours dies, as if by underpopulation.  
- any live cell with two or three live neighbours lives on to the next generation.  
- any live cell with more than three live neighbours dies, as if by overpopulation.  
- any dead cell with exactly three live neighbours becomes a live cell, as if by reproduction.  
  
in this case boulders represent live cells and dirt and space dead cells. any other objects are ignored and just left as they are. if there was dirt or space which had exactly 3 neighbour boulders (all 8 adjacent squares are counted as neighbours), the object will become a boulder. and if the object was a boulder then it will stay alive if there are 2-3 neighbour boulders, otherwise it will die and become dirt. transitions are made simultaneously so that transitions which are made during the same round don't affect the result of other transitions. this is done by double buffering the game field and therefore there's no bd-style "scanning order"  
  
it's quite funny that after applying the game of life rules, a glider was formed on the center left side. it's an iconic game of life formation and is the smallest moving formation. because of that formation i probably could have removed the "but that's life" hint and still someone would have realized what's going on :)  
  
john horton conway, the inventor of game of life, died on 11.4.2020 because of covid-19. r.i.p.

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2020-07-12 16:12 DarkStoorM  
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Ah, good old Game of Life.  
  
There is a BFly formation from the Glider!  
  
Bfly+dir  
  
   BR  
      BR  
BL BU BL

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2020-07-12 16:23 DarkStoorM  
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Oops, it didn't catch the spaces  
  
...BR...  
......BR  
BL.BU.BL

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2020-07-12 16:58 dustin  
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the first time i heard of the game was actually when  Arno  mentioned it in the "dancing fly formations" thread. i had a quick look at it on wikipedia and then almost forgot it again. that's why the hint "but that's life!" didn't help - i just forgot the name of the game. it was only when  Arno  wrote he discovered a glider formation that i remembered it, because the keyword "glider" was the reason for me to look it up back then ;d

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2020-07-12 17:30 Arno  
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 darkstoorm : indeed a dff! this one is described in more detail in episode 15 of the dff article series:  
<a href="http://www.boulder-dash.nl/forum/viewtopic.php?t=636&postdays=0&postorder=asc&start=90" target="external">http://www.boulder-dash.nl/forum/viewtopic.php?t=636&postdays=0&postorder=asc&start=90</a>  
  
but until now i didn't realize that one of it's phases looks like the glider from 'life'; that's very cool! ;-D