I've seen several excellent images regarding beer mugs, wine/champagne glasses, cans etc., but have noticed some difficulty in coming up with realistic beer foam.

I know *I* can't do it, but this forum has numerous amazing artists on it, and I wondered if a challenge might be thrown down to see who can come up with some great foam! I did see an image by RUSS-USSR that had some amazing foam, both on top of a glass and inside a bottle. I'd love to see "the pros" go for it, as I've had great difficulty in trying to recreate realistic foam.

Or perhaps even more difficult, how about some condensation on a can of pop or beer?

If these topics have already been hammered out, I apologize in advance.