Torus

rr = 3; r = 1;
ParametricPlot3D[{Cos[u]*(rr + r*Cos[v]), Sin[u]*(rr + r*Cos[v]), r*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"]

• rr is the distance from center of torus to tube center.
• r 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]