\load[minim-mp] % from TeXlive 2022

text \directmetapost{
   beginfig(1)
      draw (20,20)--(0,0)--(0,30)--(30,0)--(0,0);
   endfig;
} 
uff
\bigskip

\directmetapost{
   beginfig(2);
      u=1cm;
      draw (2u,2u)--(0,0)--(0,3u)--(3u,0)--(0,0);
      pickup pencircle scaled 4pt;
      for i=0 upto 2:
         for j=0 upto 2: drawdot (i*u,j*u); endfor
      endfor
endfig
}

\bigskip

\directmetapost{
   beginfig(28);
      path p[];
      p1 = fullcircle scaled .8in;
      z1=(.75in,0)=-z3;
      z2=directionpoint left of p1=-z4;
      p2 = z1..z2..{curl 1}z3..z4..{curl 1}cycle;
      fill p2 withcolor .4[white,red];
      unfill p1;
      draw p1;
      transform T;
      z1 transformed T = z2;
      z3 transformed T = z4;
      xxpart T=yypart T; yxpart T=-xypart T;
      picture pic;
      pic = currentpicture;
      for i=1 upto 2:
         pic:=pic transformed T;
         draw pic;
      endfor
      dotlabels.top(1,2,3); dotlabels.bot(4);
   endfig;
}


\end