one caveat... i do not recommend this for people who move often! after moving the bricks a few times, it does not seem like such a brilliant idea!
the shelves do not have to line up exactly (i prefer they don't); however, for stability, it's better that the bricks do line up horizontally. notice the shelves are not equally spaced vertically either...by experience (and those good old structures classes), i figured out that the main trick is in the profile... (1) the bricks in each section step back 1/4" to 1/2" towards the wall with the top section directly against the wall and (2) something of significant weight should sit on the top shelf (i store glass vases on top).
total cost: approx. $30
