So I thought I'd give it a go. I didn't quite make it. This one took me about an hour and a half. But it is definitely more loose than my normal painting so it was a good exercise. Here's what I did:
"Fire in the Mist"
5"x7" oil on canvas.
Here I was focusing more on gesture and complimentary colors instead of detail. Movement and contrasting orange against blue.
Have you tried the "One hour" exercise?