I made this painting for my boyfriend for his birthday last year and it took under an hour. All you need is:
-Several colors of acrylic paint (match it to colors in the room)
-Acrylic paint extender
-foam brushes
-Metal Roofing Shingles (these are the pieces used for the corners of chimneys...I found a large pack of them at Menards for $6...any hardware store should carry them)
-foam pop up craft stickers
-super glue
-canvas
First I started in one coroner and put thick lines of different color paint squirted directly from the bottle onto the canvas facing the same direction. I then poured a little amount of the paint extender as well. I just took a foam brush blending the colors just enough so that it wasn't fully mixed. I repeated this in different directions until the canvas was to my liking. The great thing about the paint extender, is you can keep redoing it until you're satisfied. After the paint had dried, I used the super glue to put the foam pop up stickers on the backs of the roofing shingles. Even thought they are already sticky on each side, they won't hold the metal pieces. I varied the heights of the foam dots by putting more than one foam dot on some opposed to others. I then just placed them in different direction and let them dry. And that is really all there was to it! You can use any material, do any pattern in the paints...the possibilities are endless! Here are some other views...
I also varied the metal shingles by taking sand paper and scratching designs into them so the light would reflect differently.
This was a small one I made just using paints, a little quick spray of spray paint, and iron on studs...