Построение трехмерного объекта и анимация поворота

uses crt,graphabc,Events;
type Cube=array[1..8] of real;
var
i,e:integer;
a:real;
xx,yy,zz:array[1..8] of real;
x1,y1:array[1..8] of integer;
const
ang=pi/3; r=100;
x:cube=(0,r,r,0,0,r,r,0);
y:cube=(0,0,0,0,r,r,r,r);
z:cube=(0,0,r,r,0,0,r,r);
procedure showcube(c:byte);
begin setwindowsize(640,480);
line(320,240,640,240);
line(320,0,320,240);
line(320,240,0,560);
textout(300,5,'Y');
textout(620,250,'X');
textout(120,450,'Z');
setpencolor(RGB(c,c,c));
line(x1[1],y1[1],x1[2],y1[2]);
line(x1[1],y1[1],x1[4],y1[4]);
line(x1[1],y1[1],x1[5],y1[5]);
line(x1[2],y1[2],x1[3],y1[3]);
line(x1[2],y1[2],x1[6],y1[6]);
line(x1[3],y1[3],x1[7],y1[7]);
line(x1[3],y1[3],x1[4],y1[4]);
line(x1[4],y1[4],x1[8],y1[8]);
line(x1[5],y1[5],x1[6],y1[6]);
line(x1[5],y1[5],x1[8],y1[8]);
line(x1[6],y1[6],x1[7],y1[7]);
line(x1[7],y1[7],x1[8],y1[8]);
end;
begin
for e:=1 to 360 do
begin a:=pi/180*e;
for i:=1 to 8 do
begin
xx[i]:=x[i];
yy[i]:=y[i]*cos(a)-z[i]*sin(a);
zz[i]:=z[i]*sin(a)+z[i]*cos(a);
x1[i]:=round(xx[i]-zz[i]*cos(ang)/2)+320;
y1[i]:=round(yy[i]-zz[i]*cos(ang)/2)+240;
end;
showcube(25);
setpencolor(15);
write(e);
delay(100);
clrscr;
e:=e+1;
end;
showcube(25);
end.