...$symmetry$^1.1

Gear image by Inductiveload [Public domain], via Wikimedia Commons, https://commons.wikimedia.org/wiki/File%3ASpur_Gear_12mm%2C_18t.svg

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...$symmetry$^1.2

Aircraft image by Kaboldy (Own work) [CC BY-SA 4.0], via Wikimedia Commons, https://commons.wikimedia.org/wiki/File%3ABoeing_747-400_3view.svg

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...

Image by Charles Edward Inglis [Public domain], via Wikimedia Commons, https://commons.wikimedia.org/wiki/File%3AInglis_bridge_patent.png

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... norm^9.1

Euclidean norm for $\bm{x} \in {\mathbb{R}}^n$: ${\left\lVert\bm{x}\right\rVert_2} = \sqrt{\sum_{i=1}^{n}{x_i^2}}$

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