Coffee Mug Stains,

for the wheels, 

photographs Carter Asmann, and graphite pencil for the finer detail,

these are the work of artist and illustrator Carter Asmann,

working from San Diego, California he draws motorcycles, 

and cars, 

it seems strange looking at the random thickness of the coffee cup stains to the intricate detail of the motorcycle or car, to see more of Carter's work have a look here at his Instagram account.