Mobius.ipynb

Kernel: SageMath 9.0

%display typeset
var('s,t')

R=2
def x(s,t):
   return (R+s*cos(t/2))*cos(t)

def y(s,t):
	return (R+s*cos(t/2))*sin(t)

def z(s,t):
	return s*sin(t/2)

cm = colormaps.Greens
def c(s,t):
	return 0.5+0.5*sin(t)**2

S=parametric_plot3d((x(s,t), y(s,t), z(s,t)), (s,-1,1), (t,0,2*pi), color = (c,cm))
show(S)

Bord = parametric_plot3d((x(-1,t), y(-1,t), z(-1,t)), (t,0,2*pi), color="red", thickness =3)
show(S+Bord)