Part of the Casswiki article series Cassiopaean Experiment
This is a Cassiopaean term for paths that cross.
We could see this as a word play on the more common concept of parallel realities. While parallel realities do not touch, perpendicular ones eventually do.
The idea is that reality is divided into realms inside realms. A realm is a division “vertically” as in density and “horizontally” as in location in space/time and in terms of choosing one out of a number of possible scenarios. Individuals themselves along with their possible life paths are realms embedded into larger realms. The intersection of these realities is at the point of the Wave, when the different densities and perpendicular scenarios intersect in a sort of multidimensional overlap. This is a sort of cosmic crossroads where passage between densities and influencing the relative probability of diverse pasts/presents/futures is more possible than otherwise.
The idea of crossing paths and colinearity are related. Paths that are ‘collinear,’ i.e. going in the same direction are more likely to cross or form perpendicular realities. These can be pictured as lines converging towards a common center, for example all traveling due north on a sphere will meet at the north pole, where the seemingly parallel northbound tracks actually cross.
The Cassiopaea transcripts discuss perpendicular realities in many places.