Having an identical twin is a little like having an echo of yourself. You're not identical, not really. You have different opinions, prefer different foods. But there's also a commonality most siblings don't have. You share some of the same strengths and talents. And maybe some things that aren't so great.
My twin sister, Sharon, and I were like that, especially when we were young. We were both math whizzes. We took advanced classes in high school and knew early on what we were going to be: CPAs. Then one day in algebra I noticed Sharon squinting at the blackboard.