While rooting around in the basement today, I came across the small perfboard project shown below that I probably made sometime around 1980. It has an LM324 quad op amp chip, 16 resistors, 6 capacitors, "in," "out" and "aux" terminals, and some kind of 4-pin block on one side. (Also what appears to be a small diode hidden by that big capacitor.) It appears from the reverse side that three of the LM324's four op amps are wired-in. I see that in building it I made use of both solder and wire-wrap.
I very definitely would not have had the ability to design it myself, so it would have come from something I was reading at the time -- various magazines, Forrest Mims, possibly though less likely Steve Ciarcia?
Just off the top of anyone's heads, any thoughts on what kind of purpose this might have had, or how it would be used?