tdplotsetmaincoords{70}{0}
begin{tikzpicture}[tdplot_main_coords]
defRI{2}
defRII{1.25}

draw[thick] (RI,0)
  foreach x in {0,300,240,180} { --  (x:RI) node at (x:RI) (R1-x) {} };
draw[dashed,thick] (R1-0.center)
  foreach x in {60,120,180} { --  (x:RI) node at (x:RI) (R1-x) {} };
path[fill=gray!30] (RI,0)
  foreach x in {0,60,120,180,240,300} { --  (x:RI)};

begin{scope}[yshift=3.5cm]
draw[thick,fill=gray!20,opacity=0.5] (RII,0)
  foreach x in {0,60,120,180,240,300,360}
    { --  (x:RII) node at (x:RII) (R2-x) {}};
end{scope}

foreach x in {0,180,240,300} { draw (R1-x.center)--(R2-x.center); };
foreach x in {60,120} { draw[dashed] (R1-x.center)--(R2-x.center); };
end{tikzpicture}