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uses
  {vgaSCRN,}crt;

const
  Balls = 900;  {if program too fast increase: if too slow decrease}

type
  movement= record
    x,   y : integer;  { position }
    dx,  dy : integer;  { velocity }
    ddx, ddy : integer;  { acceleration }
    color    : integer;
    MaxYValue: integer;
  END;

VAR
  ch : char;           {for readkey}
  I  : integer;
  Ball : array[1..BAlls] of movement;

procedure PutDot(x,y,color:integer);
begin
  Mem[$a000{VGA_Segment}:(y*320)+x] := color;
end;

Procedure VideoMode ( Mode : Byte );
Begin { VideoMode }
  Asm
    Mov  AH,00
    Mov  AL,Mode
    Int  10h
  End;
End;  { VideoMode }

BEGIN {MAIN}
  videoMODE($13); {320x200x256c}
  {init all balls}
  FOR I:=1 to BAlls do
  BEGIN
    With ball[i] do
    BEGIN
      ddx := 0; { constant horizontal acceleration }  {gravity < or >}
      ddy := 0; { constant vertical acceleration } {gravity ^ or v }

      { in this case there is NO gravity pull from ANY direction: weightless}
      dx := Random(2)-1;             { initial velocity < or >}
      dy := -1;                      { initial velocity ^ or v}

      x := i mod 305+random(15)+1; { initial coordinates, as }
      y := I mod 190+random(10)+1; {   you specified }

      { 320 * 200 positioning : take I and remainder when divided by 'balls'
        to produce a sequential increment that does not over flow 320 or 200;
        plus a random to give the fuzzy line effect}

      color:=Random( I div ((I div 254)+1)) + 1;  {Each Balls color}
      { This formula will take a loop from 1 to [any number] and make it so it
        will increment from 1 to 255 [valid color assignments]}
      MaxYValue:=Y+1;  {future use only}
    END; {with}
  END; {for do loop}


  WHILE not(keypressed) do
  begin
    FOR i:=1 to Balls do
    BEGIN
      With ball[i] do
      BEGIN
        putdot(x, y, 0);    { blank out the pixel drawn on the last
        iteration } dx := dx + ddx;     { updating velocity }
        dy := dy + ddy;
        x  :=  x +  dx;     { updating position }
        y  :=  y +  dy;
        IF x< 1 then
        begin      {hits left of screen}
          X:=1;
          dx:=dx*-1;           {moves it to the right}
        End;

        IF x > 319 then
        begin   {hits right of screen}
          x :=319;
          dx:=-dx;             {moves it to the left}
        END;

        IF y > 190 then
        begin   { BOUNCE! }
          y := 190;
          dy := -dy;            {not used: all object float upward not down}
        End;
        putdot(x, y, color);  { draw the pixel at the new position }
      END; {WITH}
    END; {for do loop}
  End; {KEYPRESS}

  videoMODe($3);          {back to text mode}
end. {PROGRAM}

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