The sides, not the corners, should be aligned with the cardinal points of the compass. It is true that we have magnetic adjustments to make according to our planetary location. Since these corrections vary, I have always recommended that one should instead use the Celestial Pole Star, which is the best method. There are different ways to do this. You have access to a chart of the star-lit heavens (libraries have these in astronomy books.) If you havn't already found a way to identify the North Star faintly shining off the end of the cup in the Big Dipper, you can otherwise look into local street maps. If necessary, check with the road department where you live. In most cases, due to the U.S.G.S mapping of township, range and section lines done about 80 years ago, many towns and streets have been designed with "Celestial North," serving as the "True" bearing for all cardinal points. So check with the alignment of the street or highway running in front of your home; and the layout of your house lot itself. In this situation, you can "eye-ball" the right direction and use that as a guide. Research over the years shows that a properly constructed pyramid can deviate from "True North" by up to 5 degrees either way off north, before any noticeable loss of pyramid energy could be made. Hope these suggestions are of helpful.