Exercise for CG Cookie's "Modeling with Modifiers" course. Assignment was to create a wheel with spokes/tire/rim, using modifiers where possible. The spokes, spoke caps, rim, and tire made heavy use of the Mirror, Array, and Subsurf modifiers. Punching the holes in the axle for the spokes was done with a Boolean modifier, which...I will probably never do again. Getting the topology to be clean enough for subsurf to work correctly after the Boolean modifier was applied required me to practically rebuild the whole thing from scratch. Maybe I just don't know how to use Booleans correctly. Maybe I need better techniques for retopo work. Likely both. :) Overall, a fun and challenging modeling exercise!