We used to fit all the diodes then use a pair of contacts connected to a high current supply to blow the unwanted ones. The diodes make (and still do) a nice li

We used to fit all the diodes then use a pair of contacts connected to a high current supply to blow the unwanted ones. The diodes make (and still do) a nice little flash as the internal point contact blows. IIRC you could tell which ones were blown by close inspection (we weren't doing it for obfuscation though).