{**********************************************************************}
{ A set of concentric circles and four sets of symmetric arcs		}
{**********************************************************************}

procedure arc_demo;
const
MONO = 5;
COLOR = 4;
VMONO = 7;
WHITE = 15;
var
i,r : integer;
begin
	clear_screen;
	i := get_display_type;
	if i = MONO then set_mode($0F)
	else if i = VMONO then set_mode($0F)
	else if i = COLOR then set_mode($0E)
	else set_mode($10);

	for r := 20 downto 15 do		{ Draw 6 circles	}
		arc(320,100,320+5*r,100,0,360,WHITE);
	for r := 14 downto 1 do	begin		{ Loop over size	}
						{ Draw next four arcs	}
		arc(320,100,320+5*r,100, 22, 66,WHITE);
		arc(320,100,320+5*r,100,112,156,WHITE);
		arc(320,100,320+5*r,100,202,246,WHITE);
		arc(320,100,320+5*r,100,292,336,WHITE);
	end;

	i := integer(readkey);
	{--- Set default text mode					}
	i := get_display_type;
	if i = MONO then set_mode(7)
	else if i = VMONO then set_mode(7)
	else	set_mode(3);
end;