They did something similar with core memory to create ROM. They inserted a core where they wanted a 1 output and left the core off where they wanted a 0 output. It was referred to an "Core On A Rope" and was used in the Apollo space craft. I had a chance to buy several of them about 15 years ago but didn't do it.
Part of the description from Wikipedia?
"Core rope memory is a form of read-only memory (ROM) for computers, first used in the 1960s by early NASA Mars probes and then in the Apollo Guidance Computer (AGC) designed and programmed by the MIT Instrumentation Lab and built by Raytheon.
Contrary to ordinary coincident-current magnetic-core memory, which was used for RAM at the time, the ferrite cores in a core rope are just used as transformers. The signal from a word line wire passing through a given core is coupled to the bit line wire and interpreted as a binary "one" while a word line wire that bypasses the core is not coupled to the bit line wire and is read as a "zero". In the AGC, up to 64 wires could be passed through a single core."