The Para-Rigger

Math professors can't agree on answer to Singapore High School Math Olympiad problem

http://www.theguardian.com/science/alexs-adventures-in-numberland/2015/apr/15/why-the-cheryl-birthday-problem-turned-into-the-maths-version-of-thatdress

Some think that there may be 2 valid answers.

AMAZING PIECE OF HISTORY -- Beginning of the Israeli air force

A TRUE STORY, NOT KNOWN BY MANY . . THE ONLY FIGHTER PLANES ISRAEL HAD WHEN THE WAR OF INDEPENDENCE (MAY 1948) BEGAN WERE SMUGGLED IN FROM CZECH REPUBLIC. THEY WERE GERMAN MESSERSCHMITT BF-109'S. THEY WERE ASSEMBLED OVERNIGHT IN TEL AVIV AND WERE NEVER FLIGHT TESTED. THIS IS A SHORT VIDEO ABOUT THEIR PILOTS. WATCH IT. YOU WILL NOT BE DISAPPOINTED.

https://vimeo.com/54400569

Here is what a Messerschmitt 109 looks like up close:

https://www.youtube.com/watch?v=BzUUlO6ihwE

How flight tracking apps work

http://www.fastcompany.com/3044490/how-flight-tracking-apps-work

This is the beautiful Cotswald village of Bourbon-on-the-Water. Inside the village there is a model of the village. The model, too, has a model of the village, including the model, which also has a model, recursively, and so forth.