Van Elk’s "Touwsculptuur / Rope Sculpture", a spatial form whose biomorphic formation gives the sensation of it being almost alive, is typical for the “slack” artworks from his a-dynamic period. The material is what it is: sculpture made of ropes. This shows his heartfelt conviction that there is no such thing as a noble hierarchy of materials. With "Touwsculptuur / Rope Sculpture", the negative space is as much a part of the work as the lengths of rope. The viewer’s perceptual l experience and their physical relationship to these forms give them the immediacy of a chance interaction.

The loose natural form of "Touwsculptuur/ Rope Sculpture" contributes a sense of the possibilities arising from post-minimalism, that balanced an economy of materials with rigorous conceptual, and philosophical intention. This work was among those that garnered the attention of famed curator Harald Szeemann in the late 1960s. In 1968 Szeeman met with the artist at his home in Amsterdam where they discussed his ideas which ultimately led to the inclusion this work in the landmark show, "Live in Your Head: When Attitudes Become Form" in 1969.