In 2012 my sister bought me a book with a page every day for a year for a sketch. I used it to practise my drawing. When I finished it I needed a new challenge. So I set myself the challenge of explaining something with a sketch - as explaining is a handy skill. Thus here we are.
They are drawn in Moleskine storyboard sketchbooks (quite hard to find in stores). I have three Uniball Vision Elites and use a Copic marker for the grey. I think it is the best combination of pens there is.
They are all first time, no corrections sketches.
Tip from Jakub at Wireframes.