functionGraphPointArrays returns an object instead of an array
make real blue (& imaginary brown)
points3D array
3d graph paths & checkbox
over and under paths
thicken path strokes for over/under visibility
start shadow path
draw shadow path
Merge branch 'dev-3d-shadow' of git@github.com:pdorrell/domkol.git into dev-3d-shadow
dashed 3D path
put negative path under canvas
a 2nd shadow
toggle 3d & explain "winding number"