WireWrap - I still have nightmares about the 'bzzzzrk' tool used to do this. I spent many hours wire-wrapping part of a 32bit bit-slice processor many many years ago. mind numbing work.

How many of you have come across "multiwire" boards? Around the time of me wire wrapping there were multiwire boards- basically a pcb substrate where thin magnet wire was routed by a nc machine and coated in epoxy, the holes drilled and plated much like a pcb. Very high density for the day.

http://www.hitachi-chemical.com/products_...pwb_05.htm