An apparatus comprises a first fastener part having a first set of mating features and a second fastener part having a second set of mating features. Coupling the first set of mating features with the second set of mating features, such that the first set of mating features contacts and at least partially overlaps the second set of mating features, forms a fastener having a channel with a hexagonal cross-section. The channel is configured to receive a plurality of fibers. Coupling the first fastener part to the second fastener part clamps the plurality of fibers in a hexagonal packing configuration.