Torus

majorRadius = 3;
minorRadius = 1;
ParametricPlot3D[
{Cos[u]*(majorRadius + minorRadius*Cos[v]), Sin[u]*(majorRadius + minorRadius*Cos[v]), minorRadius*Sin[v]},
{u, 0, 2*Pi},
{v, 0, 2*Pi},
PlotPoints -> 100,
Axes -> False,
Boxed -> False,
BoundaryStyle -> Directive[Black, Thin],
PlotStyle -> Directive[White, Opacity[0.7],
Specularity[10, 20]],
Lighting -> "Neutral"]

• majorRadius is the distance from center of torus to tube center.
• minorRadius is the radius of the tube.
• u controls the torus sweep.
• v controls the tube's profile sweep.

ParametricPlot3D[{2*Cos[u] + Cos[v]*Cos[u], 2*Sin[u] + Cos[v]*Sin[u],
  Sin[v]}, Element[{u, v}, Disk[{0, 0}, 3]], PlotPoints -> 20,
 MaxRecursion -> 0,
 PlotStyle ->
  Directive[Green, Opacity[1], EdgeForm[{Thickness[0.001], Blue}],
   FaceForm[Red, Yellow]], Axes -> False, Boxed -> False]