Shape Cloud (3.5e Spell)

The heavy smoke parted, allowing the archers a clear shot of the enemy forces.

You can reshape a pre-existing cloud, be it natural fog or smoke, or a magical effect like cloudkill. By concentrating you can move a portion or all of the fog up to 20 feet each round and make it into any shape you want, as long as it takes up the same number of squares it did previously. For example a fog cloud spell is 20 foot high and 20 feet radius. You can shape it into a wall or a tower, or poke holes in it, but the total number of foggy squares is the same.

With a Craft (Sculpting) check you can shape it into something recognizable, though it's still made of fog, smoke, or whatever the gas in question is.

Focus: A weathervane.