GC Coaching's Ham Sandwich features sweet spot over/unders, with 30/30s "sandwiched" in between. The over/under intervals are alternate between 2 minutes @88% FTP and 30 seconds @110% FTP. The 30/30s up the ante a bit and alternate between 30 seconds @130% FTP and 30 seconds @50% FTP. Yes, there are rest breaks, but they are purposely short to keep the heart rate and metabolic demands up, and I dislike rest (kidding!) Better eat your sandwich quick before the bread gets soggy...