The computer medium offers great experimental and learning possibilities. I frequently do a series of abstract color and design studies like these. They are quite easy and fun to produce. These studies can also be used as sketches or ideas for larger acrylic paintings. They were all done using the Photoshop Elements 2.0 program. You don't need the more expensive and complicated versions of Photoshop to create images like these.
I usually begin by just creating a flat color background, then I start by adding various shapes. Try it, you'll enjoy it.