Complex sentence: During the 2004-05 AHL season, an experimental rule was implemented for the first seven weeks of the season, instituting a "goaltender trap zone", more commonly called "the trapezoid" in reference to its shape.
Split into simpler sentences: During the 2004-05 AHL season, an experimental rule was implemented for the first seven weeks of the season. This additional area behind the goal line is officially referred to as the "Goaltender Trap Zone", but is more frequently called "the trapezoid" in reference to its shape.