delimiters ();
autorounding:=2; smoothing:=1;
proofing:=1;
openwindow 5 from (0,0) to (400,400) at (-100,300);
def proofrule(expr a,b) =
	special "rule"; numspecial xpart a; numspecial ypart a;
	numspecial xpart b; numspecial ypart b enddef;
def dot expr a = special " 1"; numspecial xpart a; numspecial ypart a enddef;
edges ee; ee:=nulledges;
def draw expr p = addto ee doublepath p withpen pencircle enddef;
def right=(1,0) enddef;
def pensquare = makepen ((-.5,-.5)..(.5,-.5)..(.5,.5)..(-.5,.5)..cycle) enddef;

def next =
	display ee on 5;
	proofrule ((-10,0),(100,0));
	proofrule ((0,-10),(0,100));
	shipout ee;
	ee:=nulledges;
enddef;

dot (8,10) scaled 20;
dot (0,2) scaled 20;
dot (2.5,0) scaled 20;
dot (8,0) scaled 20;

pausing:=1;
path a;
a=(8,10)..tension 1.2..(0,2)..(2.5,0){right}..(8,10){1,10}
 & (8,10){-1,-10}..bounded..(8,0){right};
draw a scaled 20; draw a shifted (200,50); next;
draw a scaled 20; draw a xscaled 20 yscaled 30 shifted (200,0); next;
draw a scaled 20 slanted 1/6; next;
draw a scaled 20 slanted 1; next;
draw a scaled 20 slanted 1/6 rotated 60; next;
def drawit = draw a scaled 20 enddef;
drawit withpen pencircle scaled 10; next;
drawit withpen pencircle scaled 50; next;
drawit withpen pencircle xscaled 20 yscaled 30; next;
drawit withpen pencircle xscaled 30 yscaled 20 rotated 20; next;
drawit withpen pencircle xscaled 30 yscaled 10 rotated 20; next;
drawit withpen pensquare xscaled 30 rotated 20; next;
drawit withpen pensquare xscaled 10 rotated 20; next;
drawit withpen pensquare xscaled 30 rotated 60; next;
drawit withpen pensquare xscaled 30 rotated -60; next;
drawit withpen pensquare xscaled 30 yscaled 3 rotated -60; next;
drawit withpen pensquare scaled 10; next;
drawit withpen pencircle scaled 20 slanted 2; next;
drawit slanted 1/6 withpen pencircle xscaled 10 yscaled 7 rotated 30; next;
drawit slanted -1/6 withpen pencircle yscaled 30; next;
end