Three bats for three brothers

My buddy Scott wanted to do something nice for his three brothers. He thought it would be cool to get each of them an original Batman pen and ink illustration. He asked me if I would do it and I naturally agreed, but then the waiting began. Early one morning before heading into the studio it hit me. Since these images are for three brothers, it would be really cool to somehow graphically tie them together. Yeah, there is the fact that each piece would go to a separate brother and hang on different walls possibly in different states, but they would always be tied together. I thought this formed a satisfying allegory to the bond between brothers.

Normally I'd tackle something like this on a scratch pad or sketchbook, but I was home at the time and too lazy to go on a search, so I fired up a pen tablet PC.