The threshold (die Schwelle) must be sharply differentiated from the border (die Grenze). The threshold is a zone.

Threshold (n.)

The point or level at which something begins or changes

[The threshold] is a zone shaped by precise tectonics, a region of cognition. Passage and peristyle, pronaos and portal, entry and vestibule, triumphal arch, sacred and profane […]: these lines, imaginary and tectonic, do not create boundaries, but the between, a space in the middle. The form of the threshold, as a temporal and spatial figure, is that of the “between-the-two,” of the medium that opens between two things.

decay (v.)

the spontaneous disintegration of a particle or nucleus

disintegrate (v.)

breaking up of something into parts or fragments, so that the wholeness of the original is destroyed

[...] for any system closed to all transfers of matter and energy, the mass of the system must remain constant over time, as the system‘s mass cannot change, so quantity can neither be added nor be removed. Therefore, the quantity of mass is conserved over time.

This divided body, which can only be experienced in its wholeness through the passage of the individual boundaries, no longer knows an inside and an outside, but only a permanent middle-in, no longer a boundary, but only possible margins, no transition, but only a permanent passage.

Limes (n.)

1. an ancient Roman frontier fortification

2. the value that a function (or sequence) approaches

Limes is a city of fragmentation. Made from a multitude of thresholds the city can only be understood and experienced through motion. The start and finish lose importance and fade as the city’s only constant is change. Constantly passing, the inhabitants never settle, loosing themselves in the experience of the in-between.