This error can be made for calculating the length of any curve. If you add the deltas in only one dimension, then you end up with a bounding box length measurem

This error can be made for calculating the length of any curve. If you add the deltas in only one dimension, then you end up with a bounding box length measurement that doesn't follow the contours of the curve. It's a misuse of calculus, that can be done with or without the visualization.