I long while ago, when I was working on Grammer and adding in the particle effects stuff, I added this particular ruleset:

Move down if the space below is unoccupied
Move left or right if the previous move was not possible
Move up if none of the other moves were possible

If you remove the last rule, the particles move kind of like a liquid. The reason that I added the last rule was to allow the particles to navigate obstacles. Otherwise, this happens:


A real liquid would have "leveled out" so to speak. My thought was that adding the ability to move up would result in more properties of a liquid, including fixing this problem. So, lets see how it worked:


I decided to try another method by letting the particles always be connected to a specific particle. This way, in order for one to move, they all had to go in the same general direction:

I called them worms and they could do some pretty cool things, such as exhibit capillary action. However, this is very clearly not working like a liquid (Well, if you got a bunch of worms together, it probably would act very much like a liquid, except that they can crawl up each other with no external support!)

However, though it isn't as fluid as the worms, the ruleset I originally gave also exhibits capillary action:


Anyways, I thought I would share this If you can think of other cool effects, feel free to share !

Wow those screenshots looks nice. Two of them almost looks like you're simulating Pepsi/Coke

These look really neat!  Someone should really make a game based on the capillary action...

I was going to do a simulation where there were several particles (one grayscale, the other black, so you could distinguish between the two. You could have a simple fluid one, plus the modified rule and I believe they should interact pretty nicely. If I were to drop a box, there would be no splash (the rules do not take into account transfer of energy), but it would probably sink in the "Pepsi/Coke" one and stay afloat in the other one

It would be very cool to see how the worms react with an object affected by gravity As to surface tension, the rule that has capillary action would exhibit good surface tension under certain conditions (the object would need to be big enough), otherwise, it would sink. It would also need to be flat, because if it was pointed, the particles would move out of the way. However, with just the sand/water rule, the surface tension would basically be "perfect" meaning nothing would be able to pass through it. If I added in a way to transmit energy and momentum between particles, that would help things out, too. Lat week, I gave a presentation (it only went about 70 minutes) on cellular automata and in it I described a ruleset that I still need to test. It works like this:

Take all the rules from the "pepsi/coke" ruleset and add in the following:
If the particle didn't move, add 1 to its "energy" level. Then, on the next cycle, check the pixel below. Even if it is black, if the energy level of the pixel below is smaller, swap the two coordinates. Otherwise, check left or right with the same conditions, and then finally check up.

That should cause currents in the particles and it could transfer energy to blocks pretty easily (every time it collides with a block, take a single energy unit and give it to the block, giving it some momentum and possibly buoyancy). It would also maintain capillary action. My hope is that this will give more relatable effects, even if it isn't true to nature I imagine that waves and whatnot would be possible, and if energy is only lost to the environment, this would cause a "splash" effect if you drop a bunch of particles at once.

Meh, I really need to find time to actually test this stuff :[

this uses a random insert to avoid too much in the way of predictable patterns. it's not as good at evening out, but it doesn't look as fizzy either.
:.A
:DiagnosticOff
:Fix 5
:ClrDraw
:ClrDrawr
:Full
:For(L,0,713
:95→{L1+L}End
:0→A→B→C+1→E
:Repeat getKey(15)
:.D
:If getKey(3)
:→E
:A<95+A→AEnd
:If getKey(2)
:→E
:A-(A>0)→AEnd
:If getKey(1)
:→E
:B<63+B→BEnd
:If getKey(4)
:→E
:B-(B>0)→BEnd
:If E
:If getKey(48)
:Pxl-Change(A,B)r
:0→E
:End
:End
:If getKey(55)
:ClrDrawr
:End
:.END D
:
:RecallPic
:.DRAW/MOVE
:For(L,0,356
:L*2+L1→S
:{S}→T
:{S+1}→U
:
:If T<96 and (U<64)
:!If pxl-Test(T,U+1
:U++
:Else
:If pxl-Test(T+1,U) and pxl-Test(T-1,U
:U--
:Else
:!If rand^4
:U--
:End
:rand^3-1+T→T
:End
:End
:
:!If pxl-Test(T,U
:T→{S}
:U→{S+1}
:End
:Pxl-On(T,U
:End
:
:End
:.END DRW/MV
:
:.ADD
:If getKey(54)
:!If pxl-Test(A,B
:rand^357*2+L1→S
:If {S}>95 or ({S+1}>63)
:A→{S}
:B→{S+1}
:End
:End
:End
:.END ADD
:
:Pxl-Change(A,B)
:DispGraphClrDraw
:End
oh, and how exactly did you manage those worms, xeda?

The fiziness is actually quite realistic. We just happen to be looking at very, very small amounts of water. Fish breathe the 'fizz' in real water.

You know what this needs? Fancy CG shaders and stuff.

The worms were pretty simple. All I did was make a small buffer for each worm (if it was 35 units long, use a 70-byte area). Then, get the coordinates of the tail, Pxl-Off( at that coordinate, then shift all of the coordinates down 2, get the coordinate of the head and do the same rules as the fizzy effects (move down if possible, move left/right if it couldn't move down, move up if there are no other options). Here is an older screenshot: