Sketching wireframes with Paper app

Sometimes I put my paper and pencil on a side and sketch wireframes with Paper app and Stylus on my iPad.

It works great especially for iPad app wireframes. I can draw on actual screen to have better idea about dimensions, placements, layout, colours...

Btw, as you can see, I was sketching for Grams app that I'm working on with @Sam Soffes it is fun :)

This is something I did on a London Tube journey, don't expect straight lines :D