After scoring a measly half point out of 2 prior games (7 and 11) with the famous (now infamous?) "Poisoned Pawn Variation" of the Najdorf Sicilian, Fischer seems to take the saying "If you don't succeed at first try try again" half-heartedly in Game 15 by once again playing the Najdorf Sicilian but avoiding the "Poisoned Pawn" variation with the safer 7...Be7, another line he knows extremely well.
Spassky is once again well-prepared for this line as well and after achieving a slight opening advantage once again throws it away with several second-rate moves, although in this game Bobby also seems to miss some winning chances as well and in the end an exciting battle ends up in a peaceful draw.
Halldor Petursson (1911-1976) was a famous Icelandic caricature artist who drew 18 cartoons of the match for a local newspaper. In this one, from left to right we see Spassky's seconds GM Krogius standing next to a sitting GM Geller while chief arbiter GM Schmid holds up a "Silence" sign next to Spassky who is pushing against Fischer while the assistant arbiter looks on and Fischer's bodyguard Saemi Palsson (an Iceland policeman) helps Bobby push back. You can see all the cartoons more clearly at http://www.dos.is/chess/3_halldor_postcards.html