The definition didn't specify that the shape had to be a solid color, so I went with my preference, and added a little sharing.
This took about 20 minutes, and at that, I fiddled with it a bit longer than I should. I didn't take pictures, but for those interested, there is a write-up of my process and reasoing below.
Stillman & Birn Wirebound Alpha 7 x 10 inches
Golden Fluid Acrylics: Ultarmarine Blue, Quinacridone Magenta, Hansa Yellow Medium, Gold Iridescent
1/2 inch flat
Paper mask of man with umbrella
Reasons for my choice of colors: I wanted to stick mainly with the primaries of red, blue and yellow. I also wanted colors that would pop and I love how vibrant Golden's Ultramarine is. I knew I'd get an almost neon glow from it. That seemed to set the tone for a rainy urban scene. While rain is often portrayed with cool, grayed colors in an urban setting you are more likely to have garish lights reflecting in the water.
I chose my blue and red (magenta) because they go well together. A different yellow might have been better, but it's what I happened to have on hand, lol. After thinking about, I decided to add in the Gold iridescent because it gleams, and would help give that feeling of wet sparkling in the light.
To get my paper mask, I went to the Morguefile Free Photos to find a good reference photo, and drew the outline of a man with an umbrella onto a piece of copy paper. Then I cut it out.
Using the foam brush, I covered the entire page with a thin layer of Ultramarine Blue, not worrying about streaks.
I placed the paper cut-out mask where I wanted my silhouette to be, and, using the brush, I painted everything with a thin layer of the Gold Iridescent. I didn't worry about streaks--in fact, I encouraged them. I wanted the strokes to give an impression of rain pelting down, so my strokes were all slanted. I started each stroke on the mask and then painted towards an edge of the page. I covered the entire page, but some of the blue showed through some of the gold.
At this point, I was done with the mask and tossed it.
I painted areas around the silhouette with the yellow, still allowing streaks so some of the gold and blue could still be seen. Then I painted the magenta shadows with a heavy coat of paint. Using a much thinner amount, I also added magenta in the upper corner and off to the left side, blending it into the yellow.
I mixed some of the blue and magenta together, and added some shadows on the silhouette, and into the reflections.
Then I covered everything, except the silhouette, with another thin coat of Gold Iridescent.
That was it. It took longer to write it up, than to do it.