https://substackcdn.com/image/fetch/$s_!8JEP!,f_auto,q_auto:...
because I had been entertaining myself by making toy globes out of paper and it seems this polyconic map was the one I had used (an interrupted version of this).
The more conventional way is to use gores using interrupted sinusoidal that look like a string of lobes connected at their common equatorial hip. What I was working with were more like flowers, one for each hemisphere, with the pole at the center.
Now, on a more related note (related to the actual post, not my tangent), things get complicated and interesting in 2d flatland.
There the field has to decay as 1/r because the circumference of the boundary scales as O(r). But that's the field. To get to the potential you need to integrate and then you get a function that is logarithmic.
A consequence of that is the potential does not drop to zero as you go away further. Unlike what is the case for the 3d case.
If you have heard that a random walking bird returns infinitely often but a random flying bird one doesn't, that's sorta related.
peri-cl•29m ago
Dipoles, like magnetic fields and planetary tidal forces, decay as an inverse R^3. That's less intuitive.