Кривая Безье на PascalABC.NET

program bezie;
 
uses
  GraphABC;
 
var
  step, t: real; m, j, i: integer; P: array [1..4] of point; K: array [1..5] of point;
  xn, yn: integer; R, G, B: byte;
procedure DrawBezie(step, t: real; m, j, i: integer; xn, yn: integer; R, G, B: byte);
var
  P: array [1..4] of point; K: array [1..4] of point;
begin
  P[1].X := 200; P[1].Y := 500;
  P[2].X := 250; P[2].Y := 200;
  P[3].X := 600; P[3].Y := 200;
  P[4].X := 650; P[4].Y := 500;
  Line(P[1].X, P[1].Y, P[2].X, P[2].Y, rgb(R, G, B));
  
  Line(P[2].X, P[2].Y, P[3].X, P[3].Y, rgb(R, G, B));
  
  Line(P[3].X, P[3].Y, P[4].X, P[4].Y, rgb(R, G, B));
  xn := P[1].X; yn := P[1].Y; t := 0; step := 0.01; m := 4;
  K[1].X := P[1].X; K[1].Y := P[1].Y;
  K[2].X := P[2].X; K[2].Y := P[2].Y;
  K[3].X := P[3].X; K[3].Y := P[3].Y;
  K[4].X := P[4].X; K[4].Y := P[4].Y;
  while t < 1 do 
  begin
    for j := m downto 2 do
    begin
      for i := 1 to (j - 1) do 
      begin
        while t < 1 do
        begin
          K[i].x := K[i].x + round(t * (K[i + 1].x - K[i].x)); 
          K[i].y := K[i].y + round(t * (K[i + 1].y - K[i].y));
          Line(xn, yn, K[1].X, K[1].Y, rgb(R, G, B));
          
          Line(K[1].X, K[1].Y, K[2].X, K[2].Y, rgb(R, G, B));
          
          Line(K[2].X, K[2].Y, K[3].X, K[3].Y, rgb(R, G, B));
          
          Line(K[3].X, K[3].Y, K[4].X, K[4].Y, rgb(R, G, B));
          
          t := t + step; xn := K[1].X; yn := K[1].Y;
       K[1].X := P[1].X; K[1].Y := P[1].Y;
  K[2].X := P[2].X; K[2].Y := P[2].Y;
  K[3].X := P[3].X; K[3].Y := P[3].Y;
  K[4].X := P[4].X; K[4].Y := P[4].Y;
        end;
      end;
    end;
  end;
end;
 
begin
  writeln('Цвет: ');
  write('R:');
  read(R);
  writeln(R);
  write('G:');
  read(G);
  writeln(G);
  write('B:');
  read(B);
  writeln(B);
  clearwindow;
  DrawBezie(step, t, m, j, i, xn, yn, R, G, B);
end.