I think pass two is intended to introduce additional regions of concavity (mostly by replacing straight lines), which in effect introduces a bunch of inflection points, helping creating the organic "spiny" feel, as opposed to a "bubbly" feel. Without it, the resulting caves look a bit more like if you spilled liquid on a waxy surface, and less like thorns.
If you go into the javascript and replace "for(let p=0;p<3;p++)" with "for(let p=1;p<3;p++)", and then re-execute the block in the console, you can generate run through a bunch of generations without step 2
Nothing in the description refers to individual neighbouring cells. All those numbers are counts -- if 0 to 2 of the neighbouring cells are rock, do this, etc.
You're talking about the post, or something in the source code?
In the post, it just counts how many of the 8 tiles are floor (which means 9 possibilities, including none of them). They aren't assigned index numbers.
Edit: ha, we all jumped on you. So now this is explained three different ways.
If you go into the javascript and replace "for(let p=0;p<3;p++)" with "for(let p=1;p<3;p++)", and then re-execute the block in the console, you can generate run through a bunch of generations without step 2
A diagram would help
In the post, it just counts how many of the 8 tiles are floor (which means 9 possibilities, including none of them). They aren't assigned index numbers.
Edit: ha, we all jumped on you. So now this is explained three different ways.
https://tnnt.org/