>>16
protected override void OnPaint( PaintEventArgs e )
{
    base.OnPaint( e );

    int offset = this.ClientSize.Width / 2;

    for( int x = -offset; x < offset; x++ )
    {
        int y = x * x / 100 * ( -1 ) + this.ClientSize.Height;

        e.Graphics.DrawRectangle( Pens.Black, x + offset, y, 1, 1 );
    }
}