The charts on the left show the output of several weighting functions, from 0 degrees to 180 degrees. The blue lines show y = 1, equivalent to no weighting.
The right-hand charts show the result of applying each weighting function to isosceles triangles with legs of length 1 and vertex angles from 0 to 180 degrees. The blue lines show unweighted area.
The unweighted (blue) curve peaks at 90 degrees, suggesting that the effective area metric favors angles close to 90 degrees. Functions C and D peak at 120 degrees. These functions favor oblique angles and strongly disfavor very acute angles.