"My other name"

Because Jacob knows how to write his name (Jacob) he noticed when I had signed a card for him and I didn't write J-A-C-O-B. I wrote Jake instead. He thought that I forgot to put him on the card. Since then he tells me that he has 2 names. Yesterday as we were practicing writing, he wanted to write "his other name". Forgetting about the card incident, I thought he was talking about his last name, but when he was finished, he exclaimed, "Mom! I wrote my other name!" He was so proud of his achievement, that he got the camera and took this picture himself too.
I can't believe how big he is getting that he can do these things!