From Twitter https://twitter.com/: Maths and murals: Marveling at the shape of mathematical equations in the Dutch town of Leiden http://blogs.nature.com/aviewfromthebridge/2017/11/22/maths-and-murals?utm_source=TWT_NatureNews&sf173998351=1 https://twitter.com/NatureNews/status/933360705427984384/photo/1 https://chirp.cooleysekula.net/attachment/43620