Sketchbook

One day I found an pretty much unused sketchbook in school and because I thought it would be a shame to pass and not to take it with me.
A few days later its look bored me. Grey on grey, as simple as it could be.
With black acryl color it got painted black. Then I hammered holes through the thick cardboard, what a pain.
After that I used strings to create some nice patterns.
Here is the result.