//Each triangle is divided by 3 many times
//makes: 1 bat wing

paper 0
antialias 1

command draw_sub_tri x1 y1 c1 x2 y2 c2 x3 y3 c3 level maxlevel
{
   set mx ((x1+x2+x3)/3)
   set my ((y1+y2+y3)/3)
   set mc ((c1+c2+c3)/3)
   smaller? 0 level
   {
      draw_sub_tri x1 y1 c1 x2 y2 c2 mx my mc (level-1) maxlevel
      draw_sub_tri x2 y2 c2 x3 y3 c3 mx my mc (level-1) maxlevel
      draw_sub_tri x3 y3 c3 x1 y1 c1 mx my mc (level-1) maxlevel
   }
   pen (level*100/maxlevel)
   line mx my x1 y1
   line mx my x2 y2
   line mx my x3 y3
}

command draw_tri x1 y1 z1 x2 y2 z2 x3 y3 z3 levels
{
   draw_sub_tri x1 y1 z1 x2 y2 z2 x3 y3 z3 levels levels
   line x1 y1 x2 y2
   line x2 y2 x3 y3
   line x3 y3 x1 y1
}

draw_tri 0 0 0 50 100 0 100 0 0 6
draw_tri 0 0 0 0 100 0 50 100 0 6
draw_tri 100 0 0 50 100 0 100 100 0 6