A red dot is connected with two non-elastic strings P and Q of equal length. The strings are fixed at points 1 and 2, as shown below. Consider both the strings, points 1, 2, and the red dot are all on the same plane throughout the operations. If one of the strings is fully stretched (taut) at all times, what will be the shape of the path traced by the dot? [Figure: see page 15 of source PDF]