These are ACEOs (for those of you not familiar with the tern it stands for Artist Card Edition or Original and it must measure 2.5 x 3.5 inches)
The yellow border is just a virtual mat.
I was experimenting with dabs of thick paint using a fully loaded brush. You need to really plan ahead with your color placement. As I expected they look better from a distance and I expect that this style will lend itself very effectively to certain subject matter.