Biorhythm using "Function" app

[Steve Simpkin]

On a slightly related note, a scanned article from a museum post by Bob Prosperi:

The June 1977 edition of Popular Electronics included an article "How to program calculators for fun and games" and includes 6 games for the HP-25, including Football, Spaceflight, Blackjack, Test your ESP, Battle Dive Bomber and Biorhythm forecast.

Here is a color scan of the complete article with listings, plus a few interesting ads for calculators in that same issue:

https://1drv.ms/b/s!AiI5Ei2M2Ja2mHMsEXfTUEZOz3Tk

The Biorhythm program section describes the theory of Biorhythms and also how to extend the date range of the calculation.

I suddenly feel the need to look for my puka shell necklace and mood ring...