I was unsure as to what abstract art work I was going to try to emulate, however, the one below seemed challenging to me because of the different shapes, the shading and the mixture of colors:
Here is my “replica”
Yes I am a novice on Photoshop and believe it or not, this took me more than four hours to do. It is really hard to draw using a mouse. However, after doing the tutorials on lynda.com, I realized some other ways I could have drawn the picture. I tried to pick something challenging, however I think any picture I would have picked would have been equally challenging, simply because I have never drawn anything in Photoshop and I am really basic in the software as it is.