@dabeaz I learned infinitesimals “naturally” in 9th grade — it wasn’t until the Weierstrauss limit formalization in college that I found the whole thing strange. Then I don’t think any of either fluxion, classical, or nonstandard analysis made sense to me until the past couple years.
the other dimensional shift for me came in Bill Kennedy’s explications of #golang from a machine-oriented perspective. That was the first time it finally clicked for me: code is human expressions of machine behaviors