Hi from Veracruz.....

A little brid told me I was summoned.

AFAIK a double open jaw is A to B, then C to D, assuming none are coterminals. A third component including an E, as stated earlier, would make it into a quasi-circle trip and/or a double open jaw plus an additional one way... that gets messy since the scenarios at that point are numerous. Re. VPescado's comment, an itinerary A to B, C to D does have 2 open gaps in a way, one on either end of the itinerary.

OK, back to enjoying Veracruz.... It's really a great city.