Trigonometry for Dummies
This is a doublet of doublets. If you move one doublet towards the other, for example by increasing the smaller J, the central peaks will coalesce into a single peak of double intensity (the algebraic sum of the central peaks).
A triplet is a special case of doublet of doublets (the Js are identical).
Another doublet of doublets. This time the smaller coupling is anti-phase.
If we increase the small J, we'll see another algebraic addition.
This is a triplet. Right?