The Fracturing is a common name for one of the few well-defined events in the wobbly history of the Puzzlebox, when the nature and structure of the place went through a great and mysterious change. Before the Fracturing, by all accounts, the Warps were connected via a pervasive transit and communication system, allowing inhabitants to easily move between warps and to places beyond, as well as easily stay in contact via the datasphere. This system was enabled by the 'magic mirror', a system or substance related to the Instantiator that could instantaneously move individuals from point to point. It also formed the basis of a transit nexus that allowed inhabitants of all the warps to mingle in a central gathering area, overlooked by a cubical treelike structure which may have been related to the mirror, or may have been a different entity entirely.
Since inhabitants of the Puzzlebox tend to be very long-lived if not immortal, it's not hard to find those who remember the Fracturing. However, it is rather hard to work out how long ago it was, or any details other than the broad strokes. Something about the event seems to defy easy categorization or detailed statements. However, a general outline has been pieced together from oral histories. The first signs of the event were a persistent and growing unreliability in the magic mirror system. Sometimes it would deliver folks in spots inconveniently distant from where they expected, and sometimes it wouldn't show up when called at all. Trust in the system started to decline, and most folks retreated to their own warps for fear of being stuck elsewhere. Eventually, the mirror stopped showing entirely, and the cross-warp datasphere connections that relied on it went dark as well.
The loss of the mirror network left the warps mostly, but not entirely, disconnected. There were always rumors of other ways between them, even though each warp seems to be boundless and self-contained. Contact, however, became rare and unreliable, more like venturing across unmapped oceans than taking the highway to the next city over. Each warp reacted in its own way, some experiencing great upheavals, and some simply slowly developing in their own directions without the complicating influence of outwarpers.
Over time, the connections between warps have slowly started to become better-established, with some reports of limited mirror-like travel as well as other, more underground systems being finally mapped out and made reliable. Whatever the method, it's becoming more and more common for inhabitants of different warps to mingle, and for others to arrive from outside the puzzlebox entirely. What this will mean for the development of the post-Fracturing warps has yet to be seen.
The label 'The Fracturing' (inevitably capitalized) seems to have originated in Topwarp, and it seems to have gained currency simply because it's short and evocative, but each warp seems to have its own way of talking about what happened. In Upwarp, it's "The Aleph Event", and in Charmwarp it's simply the beginning of the Tearose Era. Downwarpers often refer to "when the Puzzle looked away", and most in Bottomwarp seem to barely have noticed. If the inhabitants of Strangewarp has an opinion, they haven't said much about it.
- The magic mirror was its own willful being, distinct from the Puzzlebox, and it simply got distracted and went somewhere else.
- The mirror was in a relationship with the Puzzlebox, and there was a messy breakup.
- Someone tried to cure the Strangevirus and the 'cure' took out the rest of the mirrorstuff along with it.
- and many others...