Detail View

Parts List:

• Brick 1 x 4 (2)
• Brick 2 x 2 (1)
• Plate 1 x 6 (1)
• Plate 1 x 8 (2)
• Technic Axle 5 (1)
• Technic Brick 1 x 6 (1)
• Technic Bush (1)
• Technic Gear 8 Tooth (1)

Notes:

• The top of these bricks should be one layer higher than the plates in the back.
• Alright, this is a little confusing.  See that axle sticking off into space?  That's a 5-length axle.  The end of it goes into the Technic brick.  Then, there's an 8-tooth gear that meshes with the 16-tooth gear below it.  (For more clarification, look at the Detail picture)  You can leave that bush off of the end for now, though: you'll be putting a rotation sensor on in the next step.
• Figured out what that floating plate is for yet?  Don't worry, I'll show you in the next step.