Instead of only curvature, Einstein tried to add an additional property to spacetime called Torsion (spiral twisting) in his quest to unify the fundamental forces of nature into a single geometric framework. 

 Unfortunately, none of the attempts worked… but I think he was onto something. 

 The two most relevant attempts of his that added torsion are the Einstein-Cartan theory which hybridizes curvature and torsion, and Teleparallel Gravity which replaces curvature with torsion entirely. 

 https://en.wikipedia.org/wiki/Einstein%E2%80%93Cartan_theory

https://en.wikipedia.org/wiki/Teleparallelism

I’m betting on a beautiful variation of EC.