Dusty plasmas are beautiful things. The tiny dust particles become charged and repel each other. Sometimes they settle into a crystal pattern!
It’s amazing to think this crystal just spontaneously assembles in mid-air (mid-plasma).
Here’s a single layer of melamine particles in an argon plasma. The particles are about 0.5mm apart.
Notice each particle has 6 nearest neighbours just like the cells in honeycomb. This is an example of the honeycomb conjecture, the claim that hexagonal tiles use the smaller amount of material to tile a surface into equally sizes pieces. The conjecture dates back about 2000 years and was proved in 1999 by Field’s medalist Thomas Hales.