John D. Cook @johndcook.mathstodon.xyz.ap.brid.gy · 21/10/2026Deliberate imperfection www.johndcook.com/blog/2026/10/21/d… 000 0
John D. Cook @johndcook.mathstodon.xyz.ap.brid.gy · 17/10/2026Latest newsletter: Lagrange Points, Backdoors, and Edgar Allan Poe johndcookconsulting.substack.com/p/… 101 1
John D. Cook @johndcook.mathstodon.xyz.ap.brid.gy · 16/10/2026Monoliths and Lagrange points www.johndcook.com/blog/2026/10/16/m… 010 1
John D. Cook @johndcook.mathstodon.xyz.ap.brid.gy · 14/10/2026Pascal's triangle with odd numbers highlighted. LaTeX package for creating the illustration. www.johndcook.com/blog/2026/10/14/l… 110 1
John D. Cook @johndcook.mathstodon.xyz.ap.brid.gy · 14/10/2026The regions with the same color have the same area. www.johndcook.com/blog/2026/10/14/p… 103 3
John D. Cook @johndcook.mathstodon.xyz.ap.brid.gy · 14/10/2026The differential equation implicit in The Pit and the Pendulum by Edgar Allan Poe. www.johndcook.com/blog/2026/10/14/p… 000 0
John D. Cook @johndcook.mathstodon.xyz.ap.brid.gy · 13/10/2026The harmonic triangle www.johndcook.com/blog/2026/10/13/h… 000 0
John D. Cook @johndcook.mathstodon.xyz.ap.brid.gy · 12/10/2026Categorical models of logics www.johndcook.com/blog/2026/10/12/c… 000 0
John D. Cook @johndcook.mathstodon.xyz.ap.brid.gy · 08/10/2026New post: Privacy Policies and Modal Logic www.johndcook.com/blog/2026/10/08/p… 000 0
John D. Cook @johndcook.mathstodon.xyz.ap.brid.gy · 07/10/2026Lissajous and Bowditch www.johndcook.com/blog/2026/10/06/l… 000 0
John D. Cook @johndcook.mathstodon.xyz.ap.brid.gy · 03/10/2026Miquel's pivot theorem www.johndcook.com/blog/2026/10/03/m… 010 1
John D. Cook @johndcook.mathstodon.xyz.ap.brid.gy · 22/09/2026New post: Nathaniel Bowditch A self-taught mathematician who corrected errors in Newton and filled in gaps in Laplace www.johndcook.com/blog/2026/09/22/n… 020 2
John D. Cook @johndcook.mathstodon.xyz.ap.brid.gy · 17/09/2026Empirical fractal www.johndcook.com/blog/2026/09/17/e… 010 1
John D. Cook @johndcook.mathstodon.xyz.ap.brid.gy · 17/09/2026Vintage business cards and phone words www.johndcook.com/blog/2026/09/17/p… 010 1
John D. Cook @johndcook.mathstodon.xyz.ap.brid.gy · 16/09/2026New post on the subtlety of word vectors www.johndcook.com/blog/2026/09/16/c… 010 1
John D. Cook @johndcook.mathstodon.xyz.ap.brid.gy · 15/09/2026Vector embeddings of words can approximately satisfy conceptual arithmetic. But when you look at the numbers, this might not seem true. The numbers need to be placed in context. www.johndcook.com/blog/2026/09/15/c… 011 1
John D. Cook @johndcook.mathstodon.xyz.ap.brid.gy · 10/09/2026Bayesian OCR www.johndcook.com/blog/2026/09/10/b… 001 1
John D. Cook @johndcook.mathstodon.xyz.ap.brid.gy · 07/09/2026The error rate in Google's Ngram data is much higher than I thought. The graph below cannot be right. www.johndcook.com/blog/2026/09/07/n… 100 1
John D. Cook @johndcook.mathstodon.xyz.ap.brid.gy · 04/09/2026Unicode-based easter egg in NVIDIA's offer to buy Hugging Face www.johndcook.com/blog/2026/09/03/h… 012 2
John D. Cook @johndcook.mathstodon.xyz.ap.brid.gy · 23/08/2026The difference orbit inclination makes www.johndcook.com/blog/2026/08/22/i… 020 2
John D. Cook @johndcook.mathstodon.xyz.ap.brid.gy · 20/08/2026New post: AI-generated ASCII diagrams www.johndcook.com/blog/2026/08/20/a… 000 0
John D. Cook @johndcook.mathstodon.xyz.ap.brid.gy · 19/08/2026Ron Graham's hexagon has diameter 1 but a larger area than a regular hexagon with diameter 1. www.johndcook.com/blog/2026/08/18/b… 010 1
John D. Cook @johndcook.mathstodon.xyz.ap.brid.gy · 18/08/2026The recently proven imbalance conjecture www.johndcook.com/blog/2026/08/18/t… 000 0
John D. Cook @johndcook.mathstodon.xyz.ap.brid.gy · 14/08/2026How NASA used Hadamard matrices to transmit photos from Mars. www.johndcook.com/blog/2026/08/13/m… 000 0
John D. Cook @johndcook.mathstodon.xyz.ap.brid.gy · 11/08/2026Distribution of dog names in New York City www.johndcook.com/blog/2026/08/11/d… 000 0
John D. Cook @johndcook.mathstodon.xyz.ap.brid.gy · 09/08/2026DNA and Bessel functions www.johndcook.com/blog/2026/08/09/d… 000 0
John D. Cook @johndcook.mathstodon.xyz.ap.brid.gy · 05/08/2026Enumerating rooted trees and non-overlapping circles www.johndcook.com/blog/2026/08/05/e… 010 1
John D. Cook @johndcook.mathstodon.xyz.ap.brid.gy · 01/08/2026Counting rooted trees www.johndcook.com/blog/2026/08/01/c… 000 0
John D. Cook @johndcook.mathstodon.xyz.ap.brid.gy · 30/07/2026Comparing forward Euler and symplectic Euler ODE solvers on the preditor-prey equations. www.johndcook.com/blog/2020/09/12/s… 123 3
John D. Cook @johndcook.mathstodon.xyz.ap.brid.gy · 28/07/2026New post: Hiding data in permutations www.johndcook.com/blog/2026/07/27/h… 011 1
John D. Cook @johndcook.mathstodon.xyz.ap.brid.gy · 26/07/2026New post: The exp_q function www.johndcook.com/blog/2026/07/26/e… 000 0
John D. Cook @johndcook.mathstodon.xyz.ap.brid.gy · 22/07/2026Find all solutions to sin(x degrees) = sin(x radians). www.johndcook.com/blog/2026/07/22/d… 010 1
John D. Cook @johndcook.mathstodon.xyz.ap.brid.gy · 20/07/2026Volume to Area ratio for Regular Solids www.johndcook.com/blog/2026/07/20/v… 021 2
John D. Cook @johndcook.mathstodon.xyz.ap.brid.gy · 20/07/2026Solving a chess puzzle by asking Grok 4.5 to generate Lean 4 and Prolog code. www.johndcook.com/blog/2026/07/20/g… 000 0
John D. Cook @johndcook.mathstodon.xyz.ap.brid.gy · 17/07/2026Visualizing the number of medical codes (ICD-10 and HCPCS) that start with each letter. www.johndcook.com/blog/2026/07/17/v… 000 0
John D. Cook @johndcook.mathstodon.xyz.ap.brid.gy · 14/07/2026How ICD-10 chapters and code letters relate www.johndcook.com/blog/2026/07/14/i… 000 0
John D. Cook @johndcook.mathstodon.xyz.ap.brid.gy · 12/07/2026New post: Posterior varaince www.johndcook.com/blog/2026/07/12/p… 000 0
John D. Cook @johndcook.mathstodon.xyz.ap.brid.gy · 10/07/2026Linear interpolation calculator www.johndcook.com/interpolator.html 000 0
John D. Cook @johndcook.mathstodon.xyz.ap.brid.gy · 06/07/2026Reproducing a geometry theorem diagram www.johndcook.com/blog/2026/07/06/a… 000 0
John D. Cook @johndcook.mathstodon.xyz.ap.brid.gy · 04/07/2026The following number 888 ... 333 is prime. In the image below, the 3's are red, the 1's are white, and the 8's are blue. There are four 9's in the image that are black. 052 5
John D. Cook @johndcook.mathstodon.xyz.ap.brid.gy · 30/06/2026Silver Rectangles and the Ways of Kings www.johndcook.com/blog/2026/06/30/s… 010 1
John D. Cook @johndcook.mathstodon.xyz.ap.brid.gy · 29/06/2026Who you gonna believe: Grok or the docs? Neither. Do a test. www.johndcook.com/blog/2026/06/29/w… 010 1
John D. Cook @johndcook.mathstodon.xyz.ap.brid.gy · 28/06/2026Unpacking a bash brace expansion example by Peter Krummins. www.johndcook.com/blog/2026/06/27/b… 000 0
John D. Cook @johndcook.mathstodon.xyz.ap.brid.gy · 27/06/2026Heights of harmonic numbers www.johndcook.com/blog/2026/06/27/h… 000 0
John D. Cook @johndcook.mathstodon.xyz.ap.brid.gy · 25/06/2026Hart's theorem www.johndcook.com/blog/2026/06/25/h… 000 0
John D. Cook @johndcook.mathstodon.xyz.ap.brid.gy · 25/06/2026Incircles and excircles of Pythagorean triangles www.johndcook.com/blog/2026/06/25/i… 000 0
John D. Cook @johndcook.mathstodon.xyz.ap.brid.gy · 25/06/2026The Star Trek lemma www.johndcook.com/blog/2026/06/24/s… 021 2
John D. Cook @johndcook.mathstodon.xyz.ap.brid.gy · 22/06/2026Queens of a prime order chessboard www.johndcook.com/blog/2026/06/21/q… 000 0
John D. Cook @johndcook.mathstodon.xyz.ap.brid.gy · 20/06/2026Placing all six chess pieces on a 6 by 5 board so that no piece attacks another. Solution using Claude to generate Z3/Python. www.johndcook.com/blog/2026/06/20/z… 010 1
John D. Cook @johndcook.mathstodon.xyz.ap.brid.gy · 16/06/2026Testing pentagonal numbers www.johndcook.com/blog/2026/06/15/t… 010 1