What's New -  December, 2015



December 4, 2015: Between travel and  that Holiday at the end of the month, December will be a sparse programming month for me.  I did receive an interesting email recently from a scout troop leader which is just the kind that makes my week.  The troop built a catapult based on the a page actually provided by another viewer several years and available from my Catapult Simulator page.   Here's the email:


Building a catapult is one of the requirements for the engineering badge or the Arrow of Light, the only cub scouts achievement that can be worn on the boy scout uniform - so the Webelos 2 (older boys) in our cub scout pack in middle Tennessee had high enthusiasm for this project.

We downloaded the parts list and the pictures from DFF's "A Catapult Story" and the boys built it pretty much according to the instructions and pictures in an assembly line - one boy measured and marked the PVC, another cut the marked pieces, another   labeled the pieces, and another did a dry assembly (see picture). After we made sure it all looked good assembled, it was disassembled, PVC adhesive applied to the ends of the pieces, and reassembled (we used the sawed-off bottom of a movie theater cup for the cup). Using PVC adhesive was faster than screwing in all the pieces, as was done in the instructions - the entire catapult was cut and assembled in about an hour (easily done in one den meeting). The only other difference is that we used threaded rod for the stop - it worked, but you can see in the animation that it bends when the arm hits it. 
The boys attached streamers to the back of the projectile, so they could more easily see it in the air - you can see the tails in the launch, below. It easily gets 20 feet of height and 60 feet of range. Worked beautifully, and the kids loved it - thank you very much!
- James W, den leader

December 24, 2015:Merry Christmas!

We are just back from 10 wonderful days in Central Europe (the  Prague, Vienna, Budapest triangle) with family.  None of these will replace Lauterbrunnen, Switzerland as our favorite, however it was worthwhile and educational none the less.   We had been to Vienna many years ago but the others were first-time visits.   Both Prague and Budapest have similar geography; straddling a river with a castle on the high ground on one side and the peons living on the other side.  Both were occupied before and after WW2; first by German Nazis, then by Russian Communists.  Lots of differences in the details though.  All  three cities have large Christmas Markets where the girls spent many hours buying gifts and souvenirs while the guys sampled and compared beers, wines and brandies (e.g. Palinka in Budapest - ouch!).   Just spending time with our wide-spread family was the real highlight for me.  The children and older grandchildren are experienced travelers by now, so Grandma and I could mostly just relax and  enjoy.     

In Vienna we had a long lunch with Cristian Kranich after attending a performance of the Spanish Riding School Lipizzaners.  Christian graciously tested the "stay as long as you want" tradition of the Vienna coffee house by occupying an 8 person table alone at the classic Café Central  for several hours before we arrived, bypassing the long line of those awaiting a table.  He is an interesting fellow who is using some of my code in his hobby of analyzing Eastern and Indian flute scales.   He programs and designs/builds hardware for a niche market and is the closest to a true polymath that I have ever encountered.   Thanks for the hospitality Christian!  


As the final posting this year, here is an unpolished version of my Rectangle in Polygon program started in October.  The idea is to to find the largest  area rectangle that can be inscribed in an arbitrary convex or concave simple polygon.  ("simple"==>sides do not cross.)   A fun and challenging project that still needs some fine tuning for efficiency.