http://tex.stackexchange.com/questions/278015/how-to-draw-lune-in-a-sphere-and-shade-it-with-tikz ]]>

/S { L R } def

to travel straight.

]]>OK, I’ll keep this secret between you, me and the internet. :)

I like the dual formula; probably the analog is easier to interpret in spherical geometry.

]]>There is also a curious non-differential formula for volume one may glean from this approach. The area of a 2-dimensional cross-section is ∑(π-\theta) – 2π, so one gets a formula which is C ∑(π-\theta_e)l_e -2π Vol(P*), where P* is the dual polyhedron of all 2-planes that meet P, and C is some constant.

]]>math……….. ]]>