R311 - modelint/flatland-model-diagram-editor GitHub Wiki
R311 / 1:1
Compartment Box is partitioned with exactly one Divider
Divider partitions exactly one Compartment Box
A Divider establishes a line splitting a Compartment Box in two. By definition a Compartment Box is partitioned in this manner.
A Divider splits a Compartment Box into exactly two adjacent Partitioned Boxes.