%фрактальная лесопосадка
 beginfig(1) ;
   u:=1mm; branchrotation := 50;
   offset := 180-branchrotation;
   thinning := 0.7;
   shortening := 0.8;
   def drawit(expr p, linethickness,col) =
     draw p withpen pencircle scaled linethickness withcolor col;
   enddef;
   %A- основание B- направление роста, n - число бранчей,
   %size толщина дерева, col цвет
   vardef tree(expr A,B,n,size,col) =
     save C,D,thickness; pair C,D;
     thickness := size;
     C := shortening[B, A rotatedaround(B,
       offset+uniformdeviate(branchrotation))];
     D := shortening[B, A rotatedaround(B,
       -offset-uniformdeviate(branchrotation))];
     if n>0:
       drawit(A--B, thickness, col);
       thickness := thinning*thickness;
       tree(B, C, n-1, thickness,col);
       tree(B, D, n-1, thickness,col);
     else:
       drawit(A--B,thickness,col);
       thickness := thinning*thickness;
       drawit(B--C, thickness,col);
       drawit(B--D, thickness,col);
     fi;
   enddef;
   numeric nbr,nx,ny,ell,size;
   color col;
   nx:=10;ny:=5;
   pair A;
   for ix:=1 upto nx:
     for iy:=1 upto ny:
       nbr:=4+uniformdeviate 5;
       ell:=nbr*u;
       x:=ix*(1+1/20*normaldeviate);
       y:=iy*(1+1/20*normaldeviate);
       A:=(20u*(x+y*sqrt(2)/2),20u*y*sqrt(2)/2);
       size:=ell/5;
       col:=(uniformdeviate 1,uniformdeviate 1,uniformdeviate 1);
       show ix,iy,A,ell,nbr,size,col;
       tree(A, A+(0,ell), nbr, size,col);
     endfor;
   endfor;
 endfig;