dual quad nitrous !!?!!

Yeah - that's a cut background strap. I've always called them side-gapped but tomato tomahto. If you look at a plug for a rotary it's pribably a real side gapped plug vs cut back...
Sparks jump best off corners - and the cut back ones jump better and the thought is the spark is hotter as a result. There are all kinds of opinions on whether that's a benefit or not. I tend to believe that the flame kernel that forms, should start at the open side of the electrode and expand outward towards the exh valve without having to go around the strap. I've found that indexing to ensure this happens can yield enough of a boost to show up on a time slip. A friend used to use a special set in his car to back up record runs... But we're really talking minutia here and with multi-spark and high powered ignitions now in use there's not that much to be found there.