Uses graphabc, events,timers;

const
r=5 ;
d=7;

type
TDirection = (None, Left, Right, Up, Down);

var x,t,y,i,z,xr,yr,prin1,prin2,prin3,prin4,prin5,k,s4et,prin6: integer;
    Direction :TDirection;
    xs,ys,bufx,bufy:array[1..200]of integer;

   procedure shar3;
       begin
       SetBrushColor(clYellow);
       circle(xs[k],ys[k],r);
       end;

procedure Circl;
begin
    SetBrushColor(clBlack);
    circle(x,y,r);
end;

procedure rshar ;
        begin
        xr:=Random(WindowWidth) ;
        yr:=Random( WindowHeight);
        end;

procedure rshar2;
         begin
         SetBrushColor(clYellow);
        circle(xr,yr,r);
end;

procedure XP(Key:integer);
              begin
                     case Key of
                     VK_Left: Direction := Left ;
                     VK_Right:Direction := Right ;
                     VK_UP:  Direction := UP ;
                     VK_Down: Direction :=Down ;
                     end;
               circle(x,y,r);
               end;

             procedure pause;
                         begin
                    for i:=1 to 1 do
                    begin
                    Circl;
                    rshar2;
                    ClearWindow;
                    rshar2  ;
                    prin1:=(xr-x+r)*(xr-x+r)+(yr-y)*(yr-y)  ;
                    prin2:=(xr-x-r)*(xr-x-r)+(yr-y)*(yr-y)  ;
                    prin3:=(xr-x)*(xr-x)+(yr-y+r)*(yr-y+r)  ;
                    prin4:=(xr-x)*(xr-x)+(yr-y-r)*(yr-y-r)  ;
                    prin5:=R*R;
                    if (prin1)<=(prin5) then begin
                     rshar ;
                     s4et:=s4et+1;
                     end;

                     if (prin2)<=(prin5) then begin
                     rshar ;
                     s4et:=s4et+1;
                     end;
                     if (prin3)<=(prin5) then begin
                     rshar ;
                     s4et:=s4et+1;
                     end;
                     if (prin4)<=(prin5) then begin
                     rshar ;
                     s4et:=s4et+1;
                     end;

                      case Direction of
                      Left: begin   x:=x-d; if x<=0 then x:=WindowWidth  end;
                      Up:  begin    y:=y-d; if y<=0 then y:=WindowHeight  end;
                      Right: begin  x:=x+d; if x>=WindowWidth then x:=0  end;
                      Down: begin   y:=y+d; if y>=WindowHeight then y:=0  end;
                      end;
                    xs[1]:=x;
                    ys[1]:=y;
                    for k:=1 to s4et do
                    begin
                     bufx[k]:=xs[k];
                     bufy[k]:=ys[k];

                    end;
                    for k:=1 to s4et do
                    begin
                    xs[k+1]:=bufx[k];
                    ys[k+1]:=bufy[k] ;
                    end;
                    for k:=2 to s4et do
                    shar3;
                             Circl;
                       end;
                  end;
   begin
rshar;
s4et:=2;

   Direction := None;

   x:=WindowWidth div 2;
   y:=WindowHeight div 2;
    OnKeyDown:=XP;
    CreateTimer(150,pause);

end.