The Petrus method works by first solving a 2x2x2 block of the cube. This block is then extended to a solved 2x2x3 block. All edges are then oriented, and the remaining two sides of the cube are solved using only a few algorithms. Lars Petrus developed this method to address what he felt were inherent inefficiencies in layer-by-layer approaches, which he explains in his method's tutorial: "When you have completed the first layer, you can do nothing without breaking it up. So you break it, do something useful, then restore it. Break it, do something, restore it. Again and again. In a good solution you do something useful all the time. The first layer is in the way of the solution, not a part of it!" This method uses significantly fewer turns than a layer-by-layer approach, and is one of the most common methods in fewest moves competitions.