MathOverflow is a remarkable recent platform for research level questions and answers in mathematics. Joe O’Rourke have asked over MO wonderful questions. (Here is a link to the questions) Many of those questions can be the starting point of a research project usually in discrete and computational geometry and sometimes in other areas. Many of the questions remained open, quite a few have led to definite quick solutions, and for many others substantial answers were offered. Usually Joe’s questions (and also his MO answers) contain beautiful and illuminating pictures. Amog the highlights: Joe’s question on Billiard knots; a poetic question about “light reflecting off christman-tree balls“; rolling a random walk on a sphere – with a definite answer by S. Carnahan; Pach animals of high genus; Fair irregular dice (with a nice answer by Bill Thurston); Parabolic envalope of fireworks; Coiling rope in a box; A convex polyhedral analog of the pentagram map ; Random-polycube-shapes ; Which convex bodies roll along closed geodesics and many more. The 100th question is The rain hull and the rain ridge.

### Recent Comments

pavfer on Another Forgotten Bet: Is Don… Gil Kalai on To cheer you up in difficult t… Eitan Bachmat on To cheer you up in difficult t… 구글의 양자컴퓨터 vs 고전 시뮬레이… on Gil’s Collegial Quantum… Anonymous on To cheer you up in difficult t… Gil Kalai on To cheer you up in difficult t… Ehud Friedgut on To cheer you up in difficult t… Anonymous on To cheer you up in difficult t… Gil Kalai on To cheer you up in difficult t… Anonymous for the th… on To cheer you up in difficult t… Yuval Rabani on A Proof by Induction with a… Gil Kalai on To cheer you up in difficult t… -
### Recent Posts

- To cheer you up in difficult times 4: Women In Theory present — I will survive
- To cheer you up in difficult times 3: A guest post by Noam Lifshitz on the new hypercontractivity inequality of Peter Keevash, Noam Lifshitz, Eoin Long and Dor Minzer
- Harsanyi’s Sweater
- To cheer you up in difficult times II: Mysterious matching news by Gal Beniamini, Naom Nisan, Vijay Vazirani and Thorben Tröbst!
- Trees not Cubes! Memories of Boris Tsirelson
- A small update from Israel and memories from Singapore: Partha Dasgupta, Robin Mason, Frank Ramsey, and 007
- Game Theory – on-line Course at IDC, Herzliya
- TYI44: “What Then, To Raise an Old Question, is Mathematics?”
- Kelman, Kindler, Lifshitz, Minzer, and Safra: Towards the Entropy-Influence Conjecture

### Top Posts & Pages

- To cheer you up in difficult times 4: Women In Theory present -- I will survive
- 8866128975287528³+(-8778405442862239)³+(-2736111468807040)³
- TYI 30: Expected number of Dice throws
- Answer: Lord Kelvin, The Age of the Earth, and the Age of the Sun
- Equiangular lines with a fixed angle and other breakthroughs from Yufei Zhao's blog
- Elchanan Mossel's Amazing Dice Paradox (your answers to TYI 30)
- Aubrey de Grey: The chromatic number of the plane is at least 5
- Game Theory 2020
- Gil's Collegial Quantum Supremacy Skepticism FAQ

### RSS

Joe has become quite renowned for his figures :). He also has two new books out (How to Fold It, Discrete and Computational Geometry) that are filled with many such great images, which are produced using Mathematica I believe.

Wow, I am truly honored, Gil (and thanks, Andrew)! Gil, I owe you one. Request refereeing, whatever … 🙂

GK: my pleasure Joe, keep the wonderful question commingWonderful post!

Would it be at all possible to tag this post “planetMO” so that it can be found via mathblogging.org/planetmo ?

Sorry about the typo, there’s a ” missing — here’s a working link planetMO

On September 2018 Joe asked his 600th MO question!