“It’s so boring, Butler. I tried, really, but I don’t know how you do it. Forty-five minutes punching a leather bag.”
“So you worked on your solar plane instead of keeping your promise to me?”
“The cells were so efficient that there was juice left over, so in my spare time I designed a lightweight super-laser and built it from scratch.”
“Of course. Who doesn’t need a super-laser in the nose of their family plane?”

The Last Guardian, Chapter 15