{$A+,B-,D+,E+,F-,G+,I+,L+,N-,O-,P-,Q-,R-,S+,T-,V+,X+,Y+}
{$M 16384,0,655360}
Uses CRT;
Const vx0 = 3;
  vy0 = 2;
  v0 = vx0;
  r0 = 50;
  r02 = (r0-v0)*(r0-v0);
  d = r02 * 10 div 10;
Type ScreenType = Array[0..199,0..319] of Byte;
  DispType = Array[-r0..r0,-r0..r0] of Integer;
Var
  Screen : ScreenType Absolute $a000:$0000;
  Buffer1, Buffer2 : ^ScreenType;
  Disp : ^DispType;
  x,y,vx,vy,r2,c : LongInt;
Procedure Move(Var A,B; Count: Word);
assembler;
asm
  push ds
  mov cx, Count
  les di, B
  lds si, A
  shr cx, 1
  jz @zero
  rep movsw
@zero: pop ds
end;
BEGIN
 asm
 mov ax, $13
 int $10
 end;
 New(Buffer1);
 New(Buffer2);
 New(Disp);
 FillChar(Screen, SizeOf(Screen), 3);
 y:=0;
 repeat
 For x:=0 to 319 do Screen[y,x]:=11;
 Inc(y,10);
 until y>199;
 x:=0;
 repeat
 For y:=0 to 199 do Screen[y,x]:=11;
 Inc(x,10);
 until x>319;
 Move(Screen, Buffer1^, SizeOf(Screen));
 Move(Buffer1^,Screen,64000);
 For y:=-r0 to r0 do
 For x:=-r0 to r0 do
 begin
 r2:=x*x+y*y;
 if r2>r02 then Disp^[y,x] := y*320+x
  else
 Disp^[y,x]:=(y*(r2+d)div(r02+d))*320+(x*(r2+d)div(r02+d));
 end;
 x:=r0;
 y:=r0;
 vx:=vx0;
 vy:=vy0;
 repeat
 asm
  mov ax, Integer(y)
  mov bx, 320
  imul bx
  add ax, Integer(x)
  mov di, ax
  mov dx, -r0*320-r0
  les si, Disp
  mov ch, 2*r0+1
@next_dy: mov cl, 2*r0+1
@next_dx:
  mov es, Word(Disp+2)
  mov bx, es:[si]
  mov es, Word(Buffer1+2)
  mov al, es:[di+bx]
  mov bx, Seg(Screen)
  mov es, bx
  mov bx, dx
  mov es:[di+bx], al
  add si, 2
  inc dx
  dec cl
  jnz @next_dx
  add dx, 320-(2*r0+1)
  dec ch
  jnz @next_dy
 end;
 if ((x+vx)>=r0)and ((x+vx)<=319-r0)then Inc(x, vx)
  else vx:=-vx;
 if ((y+vy)>=r0)and ((y+vy)<=199-r0)then Inc(y,vy)
  else vy:=-vy;
 Delay(25);
 until Port[$60]=$01;
 Dispose(Buffer1);
 Dispose(Buffer2);
 Dispose(Disp);
 asm
 mov ax, $03
 int $10
 end;
END.