Square wave patterns in nature: en.wikipedia.org/wiki/Cross_se (where this image comes from)

And wave patterns in social media: search for "cross sea" and note its appearance on gizmodo in 2014, amusingplanet in 2015, azula in 2017, providr in 2018, sciencealert in 2019...all repeating the same somewhat garbled explanation of mathematical wave models and danger to shipping.

@11011110 I didn’t even realise this was possible - amaze

A Mastodon instance for maths people. The kind of people who make $\pi z^2 \times a$ jokes.

Use $ and $ for inline LaTeX, and $ and $ for display mode.