Three-loop carbyne model and simulation. (a) Molecular structure of carbyne, a one-dimensional carbon allotrope composed of sp-hybridized carbon atoms, consisting of alternating single-triple bonds. While chains of carbyne can be experimentally synthesized, they typically require heavy end-groups for stability [12, 19]. (b) A theoretical carbyne loop’, circumventing the need for stabilizing end-groups by bonding the carbyne chain to itself. (c) Example molecular model of a folded carbyne loop in a stable three-ring configuration, with imposed overcurvature of three , similar to self-unfolding laundry hampers.