Начертить узор

for X:=1 to 20 do
begin
  Rectangle(round(a),round(b),round(c),round(d));
  a:=a+0.08*a;
  b:=b+0.08*b;
  c:=c-0.08*c;
  d:=d+0.08*d;
end;

uses graph;
var gd,gm,a,da,n,xc,yc,i:integer;
    m,ax,aax,bx,bbx,cx,ccx,dx,ddx,ay,aay,by,bby,cy,ccy,dy,ddy:real;
begin
gd:=detect;
initgraph(gd,gm,'');
a:=60;
da:=a div 2;
n:=20;
m:=0.08;
xc:=getmaxX div 2;
yc:=getmaxY div 2;
ax:=xc+a*cos(45*pi/180);
ay:=yc-a*sin(45*pi/180);
bx:=xc+a*cos(135*pi/180);
by:=yc-a*sin(135*pi/180);
cx:=xc+a*cos(225*pi/180);
cy:=yc-a*sin(225*pi/180);
dx:=xc+a*cos(314*pi/180);
dy:=yc-a*sin(315*pi/180);
for i:=1 to n+1 do
 begin
  aax:=ax+(bx-ax)*m; aay:=ay+(by-ay)*m;
  bbx:=bx+(cx-bx)*m; bby:=by+(cy-by)*m;
  ccx:=cx+(dx-cx)*m; ccy:=cy+(dy-cy)*m;
  ddx:=dx+(ax-dx)*m; ddy:=dy+(ay-dy)*m;
  line(round(ax),round(ay),round(bx),round(by));
  line(round(bx),round(by),round(cx),round(cy));
  line(round(cx),round(cy),round(dx),round(dy));
  line(round(dx),round(dy),round(ax),round(ay));
  ax:=aax; ay:=aay;
  bx:=bbx; by:=bby;
  cx:=ccx; cy:=ccy;
  dx:=ddx; dy:=ddy;
 end;
readln;
end.