In this month's Installment, Rocko and Michael sketch up a Chair concept with a base molded out of recycled industrial wood waste (like those nifty shipping pallets). Notice how Michael uses a straight edge to harden up those lines once the design is set, but he uses it loosely and keeps it sketchy. The color is applied just as loosely to give the sketch some dimension and convey material breaks, but he doesn't over render it.
Check out the past episodes:
>> Episode 1: Sneaker
>> Episode 2: Smart Phone
>> Episode 3: Hydrogen Compact Car