Radar Chart from Scientific Research

Perceived line length is a function of orientation. The vertical line is perceived as being about 13% longer than the horizontal line despite being the same physical length. The line about 30 degrees from the horizontal plane is about 15% longer than the horizontal line, making it the line which makes the greatest departure from its horizontal counterpart. See Craven (1993) and Zhu and Ma (2020) for psychophysical evidence.

DOI