2-quadrant or 4-quadrant multiplier
Cadet X Multiplier is a variation on the Cadet VI Fader circuit, configured as a switchable 2-quadrant or 4-quadrant multiplier.
https://www.lzxindustries.net/product/cadet-x-multiplier/
Available as an assembled Module and as a DIY project.
This Module is currently available.
$120