This is the finished product of the Milk Crate shelves. I used standard (repurposed and free) plastic milk crates, plastic wall anchors (rated for holding 75 lbs each), and fender washers to hold the crates and books in place. One huge benefit of using found materials is that I could always procure more and add to the design. What started as a simple 4-piece diamond shape ended up being an eight-piece argyle-like shape.