I have wanted to do this right after I did it in 2d almost a year ago. The task wasn’t easy since there is exponentially more of everything and that cost cpu.
Well.. “If you wish to make an apple pie from scratch, you must first create the universe.” – said Carl Sagan and that meant study on optimizing the as3.

Here are the rules:
1. Every dot know their neighbours at up, down, left, right, back and forward.
2. Ones their Boolean ‘active’ is true they scale up and add random value to their property ‘hot’.
3. If random value is greater then their hot value they set their neighbours active to true.
4. All dot’s ‘hot’ and ‘scale’ value drops during time.

Click on them to active one random dot. Realize that what you are seeing are reactions created by change in constant system.

12x12x12 = 1728 particles

15x15x15 = 3376 particles

20x20x20 = 8000 particles

For you with fast cpu:
24x24x24 = 13824 particles