Hello,
I finally managed to create John Conway's Game Of Life in Minecraft!

In the 2D grid, you draw dots by dropping grass, all grass blocks are "alive".
You can remove the closest dot by dropping dirt, all dirt blocks are "dead".

The "game" resets itself if you drop bedrock on the ground.
The "game" starts when you go in spectator.
The "game" finishes the current cycle and then stops when you go back into creative.
(F3 + N for gamemode toggle).

Just like Langton's Ant, in each cycle things get checked, updated and a new cycle gets initiated.
The rules for the ant were simple: Check the colour, rotate and change colour based on the original colour, move on and start a new cycle. John Conway's Game Of Life is a bit more difficult, the rules are:
- All alive cells die if they have 1 or less neighbours, as if caused by underpopulation.
- All alive cells die if they have 4 or more neighbours, as if caused by overpopulation.
- Needless to say, all other alive cells with 2 or 3 neighbours survive.
- All dead cells come to life if they have exactly 3 neighbours, as if caused by reproduction.

Boring right?
No! With this simple mechanic, all the way from 1970, amazing "ecosystems" or "machines" have been created. Although I have listed all items on the Wikipedia page, your imagination is the limit and I dare you to come up with an amazing pattern and share it with me or the community. Also, I have not recreated all known patterns in minecraft. If you want to create one of the patterns that I didn't do myself, go ahead and google for it!
[spoiler="Still Lifes" (Static)]

Block


Beehive


Example of what you can do to the beehive


Loaf


Boat


Tub


Example of what you can do to the tub
[/spoiler]
[spoiler="Oscillators" (Stable)]

Blinker (2 frames)


Toad (2 frames)


Beacon (2 frames)


Cool pattern, inspired by the beacon

Pulsar (3 frames, extremely cool and complicated)


Pentadecathlon (15 frames)

Other Oscillators have been found with 4, 8, 14, 15 or 30 frames. Go ahead and find them!
[/spoiler]
[spoiler="Methuselas" (Barely Stable)]
These are all easy to build:
The R-pentomino (Takes 1103 cycles to stabilize, creates 6 gliders)
Diehard (Exception, dies after 130 cycles)
Acorn (Takes 5206 cycles to stabilize, creates 13 gliders)

A glider is a spaceship, see the next section.
[/spoiler]
[spoiler="Spaceships" (Stable & Moving)]

Glider, moves to the bottom right (According to the orientation in the image)

Lightweight spaceship (LWSS), moves to the right (According to the orientation on Wikipedia).
The spaceship is easy to build.
[/spoiler]


Why is it so slow / Why didn't you use entities?
Yeah yeah, I know, changing blocks is slower than updating an entity.
However, the grid is currently 64 x 64 blocks. Imagine having to load in 4096 cows and have them stare at you while your pc gets fried...

I hope you will all enjoy this creation!