After friends became excited about the existence of Core Rope Memory as proposed by NASA for the Apollo Guidance Computer, I decided to build a proof of concept. The concept in this case was building the memory as a literal, flexible rope. The actual implementations were normally made into a rigid assembly with the cores fixed, and the "rope" potted in epoxy.
However, I did not implement the designs NASA used, and instead used the simpler (to build and understand) Univac style.