program Balls;

uses Types, QuickDraw, Events, MiscTool;

type

  Ball = Record

    x, y, sx, sy: Integer

  end;

var

  i: Integer;

  tick: LongInt;

  r: Rect;

  b: Ball;

  balls: Array[1..15] of Ball;

begin

  graphics(320);

  clearScreen(black);

  hideCursor;

  tick := getTick;

  setPenSize(3, 3);

  { Setup balls }

  for i := 1 to 15 do begin

    balls[i].x := random mod 300 + 10;

    balls[i].y := random mod 180 + 10;

    if random > 0 then

      balls[i].sx := random mod 2 + 1

    else balls[i].sx := -(random mod 2 + 1);

    if random > 0 then

      balls[i].sy := random mod 2 + 1

    else balls[i].sy := -(random mod 2 + 1);

  end;

  repeat

    for i := 1 to 15 do begin

      b := balls[i];

      { Draw balls }

      setRect(r, b.x, b.y, b.x + 5 + i,

        b.y + 5 + i);

      setSolidPenPat(i);

      paintOval(r);

      setRect(r, b.x - 2, b.y - 2, b.x + 7 + i,

      b.y + 7 + i);

      setSolidPenPat(black);

      frameOval(r);

      { Move balls }

      balls[i].x := b.x + b.sx;

      balls[i].y := b.y + b.sy;

      if (balls[i].x < 0) or (balls[i].x > 310)

        then balls[i].sx := -b.sx;

      if (balls[i].y < 0) or (balls[i].y > 190)

        then balls[i].sy := -b.sy;

    end;

    repeat until getTick > tick;

    tick := tick + 1;

  until button(0);

end.