I've always liked these kinds of symmetrical geometric patterns. They weren't Sri Yantra as far as I know, but I found myself doodling stuff that looked similar when I was bored out of my mind listening to teachers lecture in school. I've also been fascinated with the mathematically consistent patterns that can be found throughout nature.
One of my favorite examples is in regards to sound. When you harmonize two notes together, they sound pleasant because they're two tones that have wavelengths that line up with each other periodically and reinforce each other. It has the same effect of a rogue wave in water, and those higher peaks that are created as a result is the pleasant sound that you're hearing.
I also geeked out on the golden ratio/Fibonacci stuff when I learned about it. I found that some of the numerical patterns that I had already noticed repeating in my life (addresses of people I knew, the amount of some receipt or bill, phone numbers, etc.) tended to be part of the Fibonacci sequence.
Regardless of whether these things are sacred, they are certainly part of actual nature, otherwise we wouldn't see them everywhere. I think it's just natural to notice these patterns and apply significance to them. It's fun to think about either way.
I had fun drawing the golden ratio today: