Why does this bench design call for bevels on legs?
The legs are beveled on the top and bottom so that they can lean inward a little bit. In other words, the distance between the tops of the legs is less than the distance between their bottoms. Because the bench top and feet are intended to be level, you cut a matching bevel on the top and bottom of each leg.



These inward-leaning legs work in combination with the "stretcher" (32" arched pieces) to make the bench stronger. The angle means the bottom of the legs will be pulled outward as weight is applied to the bench. However, the stretchers prevent the legs from spreading out. It's a similar structure to a sawhorse.