And lastly... here is where I earn my bread and butter.
The book illustrators at Disney had great difficulty at drawing the cyborg arm for the main pirate in the Treasure Planet Books, so they hired me to rebuild the arm from sketches (no blueprints were available) and I turned my computer into a line art drawing. And I din't use any filters! Just a bit of good old fashioned trickyness!!!!
Here is an arm I made
And here is the rough drawing it had to fit into!