|A Coordinate System|
This need not be a two-dimensional system, it could as well be something like
|A Cube; This time, in glorious 90s colours.|
One dimension might encode person, another tense, another aspect.
Since we're dealing with a very finite number of combinations - say, this time, that we're dealing with number * case * gender or something like that - we can conveniently enough flatten this cube by mapping the elements of two of the dimensions onto one dimension, returning us to something like the coordinate system above; we need to arrange it so that one dimension is subordinate to the other, though (e.g. in the multi-dimensional representation, each dimension can keep its elements in the same order everywhere: 1, 2, 3, ... always come in that order; however, if you have a subordinate and a superordinate set of dimensions, A3 may come before B1, despite 1 < 3, if the value of A is lower than the value of B). We get this happening:
But now we'l get to an interesting thing: in morphology, we have two 'spaces'/'planes'/whatever. One is the plane of possible combinations of morphemes, the other is the plane of possible combinations of meaning.
Canonical agglutination, if such a term can be used, would refer to the following situation, or higher-dimensional analogues of it:
|A system of correspondences that has been distorted in several ways.|
Some of the most common things in real-life languages probably are meaning-conflations (several meanings correspond to one combination of morphemes), morpheme-conflations (several morphemes express the same meaning). Direct twists might be somewhat unusual; however, if a twist/cross exists, I find it likely that more than one pair has a similar cross/twist going, and it's of course imaginable that the twist has more than just one pair of elements involved.