sorry it's a bit dark. My room is like that. But you can see it, can't you?
I have the same screwdriver!
that's so cool! You should do something like this! What I did was I made a sketch on one sheet of paper, taped it on the window, and taped another paper on top of it. The light of the window made the top sheet act like tracing paper and I was able to see the sketch underneath. That's when I used my invisible ink. See?