Circumstance Bell

Dangling in workshops deep within arcanist academies, and on high altars of contemplation in cluttered little alcoves of monasteries, an observant visitor will find in common they showcase the same peculiar sculptures. These strangely lobed structures are symmetrical, resembling abstract clusters of fruit, or explosions of light under a crushing ocean of darkness. Circumstance Bells represent models of probability for the interactions between the material world and other planes of existence. Used by scholars and holy warriors alike, they help to predict when and where a thinned planar boundary or passageway will allow easy transferences between the material and near planes.
Circumstance Bells come in many shapes with the simplest merely a sphere, the next a pair of ellipse like curves resembling balloons or pears pulling away from each other, another is a variation of that with four such curved shapes pulling away, and so on with more elaborate and numerous shapes for each orbit of reality expanding away from the material plane. They can be sculpted from any convenient material, but the most esoterically conscientious will seek out an artisan who can craft one from materials proposed to provide greater circumstantial resonance with the plane being studied.
Experts contest that a Circumstance Bell attuned well to the plane it is meant to represent can have sufficient resonance of its own to actually cause a thinning of the boundary, or even affect the circumstances of naturally occurring fissures or gates and pull them into proximity of the bell. Stories are told of travelers discovering fine sculptures lying on the road or in the wilderness, only to find out later it is believed to be a bell belonging to a local enthusiast of circumstance lore who has disapeared; with the conclusion that they must have been stolen away into another realm by creatures popping out of a fissure attuned to their bell capturing them.