Another neat application, if a bit simplistic, are these mechanical paper computer that let you figure out your body-mass-index. They are basically two disks with logarithmic scales on them that you rotate relative to each other. Like a slide-rule, but circular. I think you can find them under the name 'BMI wheel'.
replyThese exist for various medical usages. I've seen one to compute the due date of a pregnancy (from either the date of conception or the last missed period). This was at an obstetrician's office. It was probably dropped off by a sales rep and had the logo of some medication or other.
replyIndeed, you can get yours today https://www.instructables.com/Make-a-simple-paper-slide-rule...
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