Neither of these capture well as screen shots, but if you liked lava lamps and mid90s screen savers, you'll like these.
Scroll to the menu at the bottom of the screen.
Make the "Namekuji" vanish by clicking on it twice.
Turn off the Sand, Water, Salt, and Oil by clicking on each one five times.
Click on the Spout attribute. Draw many, many short horizontal lines. The idea is to fill the screen with water spouts and water. They're slightly different colors of blue. The final effect works best with short, horizontal lines. If you see any sections that are too much the color of water, draw in some more spouts. You may experience some lag at this point.
When the screen is filled with water, click on the Plant attribute. Now the idea is to have the plant grow all through the water. You can let the plant grow on its own, or click randomly around the screen to make it happen faster. You can let this happen in another window, or go away and do something else for a whlie.
When the plant has filled the entire screen, click on the Spout attribute again, and draw some more short lines in any sections that are too green, and through any black triangles that have formed in the rain shadow (so to speak) while the plant was growing.
Then, click on the Fire attribute. Then click once in a lower corner of the plant.
If you've drawn enough water spouts, the water will grow the plant fast enough to keep pace with the fire. I've sometimes let this screen run for more than 24 hours. I haven't watched it the whole time, mind you. But it can be stable for all its shiftingness.
Burning Oil Caves:
As above, make the Namekuji vanish and turn off the Sand, Water, Salt, and Oil.
Set the Pen-size to x32. Click on the Wall attribute, and fill the screen with a gray wall.
Click on Oil and turn it up to five. There should be a small brown rectangle in the upper right of an otherwise solid screen of gray.
Reset the Pen-size to x4. Select the Fire attribute, then click once in the oil rectangle.
The fire will quickly burn itself a small bowl in the wall. The oil falling into the screen will keep the fire sustained, but enough oil will pass unburned to fill up the bowl and reignite in a lengthening cycle.
Click on the Eraser attribute, and draw winding, downsloping lines from the bowl. Think of tree roots or cave tunnels. The oil will fill up these tunnels. When it reignites, the fires will gradually burn away the wall and widen the tunnels. As the cycle lengthens, you might, ahem, want to let it run and check back in on it every so often. ;>
Anyway, as I said, I find these hypnotic. In fact, this post has taken a long time to write because I keep going back to the Burning Oil Caves and watching for a while. Hah!