David G. Wells’ “The Penguin dictionary of curious and interesting…” books are excellent and have been great source of inspiration for me.
They are now are almost 30 years old.
What new entries would you put in these books—either because they’re new after publication, or could have (should have) been included at the time?
Some suggestions for curious and interesting ‘Numbers’ based on personal knowledge (or ignorance). What would you add?
Sum of three palindromes (Javier Cilleruelo, Florian Luca and Lewis Baxter; try it at https://somethingorotherwhatever.com/sum-of-3-palindromes h/t @christianp)
Proof of Fermat's Last Theorem (Andrew Wiles)
Twin primes conjecture is still open, but there are infinitely many pairs of primes that differ by 246 (Yitang Zhang, James Maynard and Terence Tao @tao)
Some suggestions for curious and interesting ‘Geometry’, more in my comfort zone but still plenty of ignorance 😊
What would you add?
Aperiodic monotile (Smith, Myers, Kaplan & Goodman-Strauss)
Noperthedron (Steininger & Yurkevich)
Progress in various packing problems (https://erich-friedman.github.io/packing/)
15 types of convex pentagonal tilings (Rao and others)
Solving cubics with origami (Beloch & Lill; see http://origametry.net/papers/amer.math.monthly.118.04.307-hull.pdf)
A geometry entry that could have been published at the time is the plastic ratio https://en.wikipedia.org/wiki/Plastic_ratio
But the Harriss spiral is newer https://chalkdustmagazine.com/regulars/on-the-cover/on-the-cover-harriss-spiral/
Something newer: an elegant "almost orthogonal polyhedron: a polyhedron whose adjacent faces are orthogonal to each other, except on one edge." https://www.gathering4gardner.org/g4g15gift/ExchangeArchive-AlmostOrthogonalPolyhedra-G15-093-1.pdf
h/t @robinhouston
foldworks