Wikipedia's entry on the spherical cow, illustrated for the 1996 American Astronomical Association meeting by Ingrid Kallick (https://ikallick.com/).
Ingrid Kallick, "Spherical Cow ", contributed by Prerna Srigyan, STS Infrastructures, Platform for Experimental Collaborative Ethnography, last modified 23 April 2024, accessed 5 May 2024. https://stsinfrastructures.org/content/spherical-cow
Critical Commentary
I learned about the "spherical cow" metaphor in theoretical physics in the first chapter of Chanda Prescod-Weinstein's The Disordered Cosmos. "Approximate the cow as a sphere" is a running joke for simplification of highly complex systems into symmetrical ones for easier calculations at the cost of representation. This visual metaphor characterises one aspect of the culture of particle physics today.