using Plots
plotly() # or pyplot() - gr() does not work for me
# spherical: (radius r, inclination θ, azimuth φ)
X(r,theta,phi) = r * sin(theta) * sin(phi)
Y(r,theta,phi) = r * sin(theta) * cos(phi)
Z(r,theta,phi) = r * cos(theta)
thetas = range(0, stop=pi, length=50)
phis = range(0, stop=pi/2, length=50)
xs = [X(1, theta, phi) for theta in thetas, phi in phis]
ys = [Y(1, theta, phi) for theta in thetas, phi in phis]
zs = [Z(1, theta, phi) for theta in thetas, phi in phis]
surface(xs, ys, zs)
