Some designs deserve some further tinkering. That is how I feel about the I love doubles tshirt design. I love it because I love doubles too lol XD. This personal challenge to do a design a day is really to get myself more into using abobe illustrator for design, as well as creating wearable designs that can be sold from print on demand sites like teespring.com. Its only going to get better if you commit 10-60 minutes a day to a skill you intend to be paid for.