Any deviation from a straight line indicates deviation from a perfect helix. By quantifying how much a straight line fit deviates from the cumulated sum of angles, we can find how much the MO deviates from a perfect helix. As a quantitative summary of how much a given MO deviate from a perfect helix, we report the mean absolute deviation (MAD). A higher MAD indicates deviation from a perfect helix and a lower MAD indicates that the MO is closer to a perfect helix. This deviation thus provides a rigid measure of the helicality. The MAD is given by