[ot][ot][ot][personal] whirligig small thoughts

[Undescribed Horrific Abuse, One Victim & Survivor of Many]

[wedge volume is the integral of a difference because the difference
represents the shortness of the side of a right triangle relative to
its diagonal -- the shortness of the height of a slice of a circle
relative to its total radius.
so the r_sphere^2 part should be always bigger than the x^2 part,
since abs(x) <= abs(r_sphere)