A few years back when we were cleaning out junk from a room at work we found a mat of fine wire mesh about the size of a sheet of A4. It had little metal rings evenly spaced over it where some of the wires crossed. Turns out it was memory from the computer that replaced the Leo computer we* used to use at the end of the 60s. The rings were ferrite; literally memory addresses.

*when I say 'we' I mean them, not me, I was only 14 at the end of the 60s. Slide rules were cutting edge.