Origami Great Dodecahedron

Here is a crease pattern for an origami Great Dodecahedron. This fascinating shape is something like a sunken icosahedron, and can also be seen as twelve intersecting pentagons with a raised star on each face. I tried several iterations of the layout because the details of forming tabs and pockets to close the model took some trial and error to get right. The basic idea is fairly straightforward. I use fivefold polar symmetry, and the whole pattern embedded in a single pentagon that takes up pretty much the entire square sheet. I was able to divide it into a grid of parallelograms using simple ratios. Each parallelogram then gets subdivided into the triangles that form the faces of the shape.

Since I just fold back the corners of the square to form the base pentagon, I tried a version folded from a pentagonal sheet, but this turned out not have enough extra paper around the edges to from the tabs and pockets. The pentagon’s height is slightly less than its width, which results in a then strip of unused paper at the bottom edge of a square sheet. I decided to try folding the strip around all five sides (except where it gets truncated at the corners), and that turned out be just the trick.

I’ve successfully folded a couple of these now that stay together well. Pictures as soon as I make one out of nice paper.

Spring Brake

The mild spring weather continues and we spent most of the weekend outdoors. Jeannie and I (mainly her, since my back is still recovering) did another big round of yard work, weeding, putting down mulch under the hedges, and starting with the season’s lawn mowing. The kids on our block, led by Lizzy and Michelle, took it upon themselves to clean up the trash down at the and of the street, where there is a strip of no-man’s-land lawn outside the fence to the local school athletic field. Jeannie and I were impressed with their effort and helped them out with gloves, trash bags and some tools.

I got Lizzy a new bike over the weekend too. She’s big enough now for a full size bike, with 24 inch wheels and gears and shifters and all. We went first to the big bike shop up in Scarsdale, and it was all high-end bikes that were more than I was looking to spend, and moreover the place was super crowded and there was no one to help us. So we went to Toys’r’Us, which was a much less hectic scene and they had a good selection of reasonably priced bikes. I encouraged Lizzy to pick a Schwinn, but she didn’t like the color (red and black, too “boy”) and instead picked a pink and white model from a brand called Rallye. It was a good deal less expensive than the Schwinn, and in most respects looks like a pretty good bike. Mountain bike frame with eighteen gears. The shifters and brake handles are made of plastic and look a bit flimsy, so it remains to be seen how they’ll hold up. Also the back brake doesn’t seem to grip as tight as it should. I adjusted it but am not really satisfied. I’ll try again before next weekend, but it’s an important part for safety, and if I can’t get it right we’re going to have to return it and keep looking. Probably hit the bike shop in Pelham next.

I also took a nice long ride (5 miles) on my rollerblades Sunday, which felt great.

Concert — Emerson Lake and No One

One evening last week Jeannie and I saw a rather unique concert. Keith Emerson and Greg Lake, of Emerson, Lake and Palmer played a show of mainly unplugged material, interspersed with stories about their songwriting and touring and that sort of thing. More intimate and laid-back than polished and high-energy, but it definitely had a few special musical moments. Most of the songs were altered or adapted to fit the format. They opened with “From the Beginning” which featured an expansive jazz intro by Keith. Next came an adaptation of the King Crimson classic “I Talk to the Wind”, played in a similar style. Quite nice and surprising. Then Greg switched from guitar to bass and it was on to “Take a Pebble” with a piano solo that segued into a mainly solo piano rendition of Tarkus. I think I preferred it to original. You could hear the piano ideas a lot more clearly, and it didn’t sound so bombastic or repetitive, and I think they tightened it up a bit and dropped a solo section or vamp here and there. Toward the end Keith fired up the Moog and did a combination keyboard and knob-twiddling solo, which left the machine in a state of generating automatic weird noise to ride out the song as he returned to the piano. Very nicely done.

The second set included a versions of “Ces’t la Vie”, “Bitches Crystal”, a semi-successful jam that took off from Blue Rondo a la Turk, a rendition of “Pirates” not quite as good as Tarkus but admirable nonetheless, and even a bit of “Benny the Bouncer” (which Keith claimed is his favorite ELP song), and of course closing the show with “Lucky Man”. At one point they opened the floor to questions from the audience and woman requested to lie down on the stage under Keith’s piano for a song, so he indulged her and spun out a fantastic improvisation for a few minutes. It was nothing I’ve ever heard before but it was reminiscent of several of his compositions, and fairly structured in its use of ostanotos, rising and falling lines and stabbing chords, and I feel like I have some new insight into “how to sound like Keith Emerson” now. All in all an interesting and enjoyable experience. I wish them the best for their plans for a reformed ELP tour this summer!

Spring Break

I took a few days off for spring break. Unlike last year, when we went on an epic journey to distant lands, this year we pretty much hung around the house, rested, got caught up on some chores and did a few fun things locally. The weather has been absolutely fantastic, more like June than April. We’ve been barbecuing almost every day. I haven’t seen a lot of the neighborhood kids since last fall, and its surprising how everyone’s grown.

All our flowers have come in beautifully, including the new flower bed by our neighbor’s garage that we planted last fall. We got rid of our little kiddie play structure slide and sandbox now that the kids have outgrown them. We covered in the low spot with dirt and blue stuff. The end of an era. Some other random tasks put us about half done with the spring yard work cycle. Still to go is getting the mulch under the hedges and turning over the garden. Plus getting the roof fixed. At least we got a few estimates and it looks reasonable. Oh yeah, and Lizzy’s gonna need a new bike this year.

We washed, waxed and vacuumed the cars for spring. I like to do that once a year. I also started up the Mustang, and it’s good to know it turned right over. No problems with the batteries or anything major like last year. When you step on the gas, however, there’s a temporary drop in power before it surges back. I noticed this towards the end of last summer, and I suspect it’s the carburetor. So I’ll taking it into the shop as soon as I get the chance.

On Easter Sunday Mary’s came over. It was a really nice visit and another great day. We had everyone sit at the dining room table rather than have a separate kiddie table in the kitchen. The end of another era. Everyone growing up fast.

Yesterday Jeannie and I took the girls on an outing to the Metropolitan Museum of Art and for a walk thru Central Park. It was a fantastic time. The Met has been on my list for about a year now. I haven’t been there in many years and had forgotten that it’s much more than just art. One of the big old classic New York museums, up there with the American Museum of Natural History, which I know pretty well by now, having visited a few times a year for origami the last few years.

In addition to paintings and sculpture, the Met has all kinds of artifacts: medieval armor, musical instruments, furniture, all kinds of metal, wood and glass vases, vessels, instruments and implements, plus ancient ancient Greek, Roman, Egyptian and Inca wings. All of it fascinating stuff. (Well maybe the furniture got to be a bit much after a while…) The armor and musical instrument galleries were probably my favorite. There are two huge wings of paintings, Modern and Classical, but I feel like we didn’t really do them justice. For one thing, the whole place is laid our like a maze rather than designed for flow-thru, and the painting galleries in particular are not well organized. They could do with some signage to tell you about what county and century you’re looking at and what is the story from hall to hall. Also looking at that many paintings is a lot information, so one tends to glaze over after a while. Still the kids seemed to get a lot out of it and so did I.

They really wanted to visit Strawberry Fields in Central Park, but it was on the opposite side. On a related note, Michelle learned how to play the intro to “Strawberry Fields Forever” on the piano.

Today I crossed off another longstanding todo item: I went and got a New York City library card. I have a card for my local library but I hardly ever go cuz I’m mostly at work when they’re open. Still, I have a long list of books I’d like to read and for most books it seems such a waste to buy it and read it once and get rid of it. The main NYC library -– the famous one with the lions on the steps -– is just a few blocks from my office. So the plan is to go there on my lunch break every week or two from now on. I’d never been inside before. It’s a pretty impressive marble edifice with giant halls and stairways, like it was carved by dwarves out a massive mountain of solid stone. There was an exhibit on old maps, which is pretty cool. Only on the third floor will you find books or librarians. Apparently most of the books are in and underground vault or in the branch library across the street. They have some kind of system for checking out books by computer. I plan on going back soon to get some books, so I’ll let you know how it goes.

Origami By Children 2010

Once again it’s time to submit entries for Origami by Children for the OUSA annual convention. This year both Lizzy and Michelle came up with some cool stuff. Lizzy made an original pureland Fancy Picture Frame and folded the Octahedron for John Montroll’s Plethora book. It’s an interesting model in that that it’s unlike most of his later polyhedra, which optimize for size and clean surface layout, this one goes for easy of folding and the general approach echoes the classic waterbomb model. Michelle folded a classic kite base Cat (I have one that I folded years ago but can’t remember the creator; maybe it’s Yoshizawa) and a Candle from Montroll’s Christmas book.

Change in the Weather

Rewinding a bit, St. Patty’s day was sort of an unusual day. We’d had a lot of stormy weather, and it was really cold that morning, and I had to get up early for physical therapy. The road there was still closed from the big storm, so I had to take a different route. By the time I was on my back home, it was already warming up outside and turning into the first really nice warm spring day. I’d been waiting for a while for my back to start feeling better, and that turned out to be the day. Such a relief.

My train was late, and when the door opened it smelled like booze. Partiers headed into the city to enjoy the parade. I was probably the only one in the car going to work. Some guy on the train noticed me folding a color-change stellated octahedron that I’ve been working on. “Dude, is that origami? Cool! Did you get that from youTube?” The parade goes right thru my neighborhood, and it’s like that the whole day, drinking and partying, like it’s Mardi Gras or Halloween or 1999. At least I was able to cross 5th Ave. without any altercations with the police this time.

At work it was all about deploying the first release candidate of our project to the Q server. This is a major milestone on what has been a really long strange trip. I was mired in config files all day, or as I’ve come to call it, configgy pudding. Our company has a mandate to try and do more thru configuration and less thru code. But it’s already becoming hard to manage, and we haven’t even deployed to live. So I need to write a config management tool so we can have instant congfiggy pudding. Anyway, we got it working, and deployed to QA, where we’re already finding bugs.

After work was a corporate happy hour function at a hotel bar which was smack in between two Irish pubs. I made friends with a management consultant who was part of a team engaged by our overlords to hang around and analyze out office’s dysfunction and presumably figure out who to fire. She seemed pretty smart and interesting/weird with a possible MIT vibe. She told me, “You don’t look old enough to have been writing software in the 90’s.” Hell, I was writing software in the 70’s. Hopefully this means I won’t be the one who gets sacked.

The mild weather continued and by the weekend we were able to get started on the spring yardwork and enjoy the season’s first barbecue. I was really tempted to get on my rollerblades or see if I could start up my Mustang after a winter of sitting in the garage, but neither one seemed like a wise idea given the condition of my back. After the weekend the weather reverted to a more typical state of dreary cold and rain, which is pretty much how it’s been for the past week. I’ve gotten a bunch of new exercises from my therapist, and have developed a new workout routine to incorporate those along with most of the stuff from my old workout. I’ve been able to bring back most of the exercises now, and am back up to 70 percent of the weight, and some of them still have limited mobility. I did go ice skating that past Saturday with my kids, and did fine, as my back continues to improve.

The kids are going thru a Beatles phase right now, which is fun because they’re one of my all-time favorite bands. It started back in January when we were watching Anthology. Then Jeannie found the DVD’s for A Hard Day’s Night, and Magical Mystery Tour on sale. (Yes MMT is as bad as everyone says. Three or four excellent music videos and an hour of filler showing people riding a bus.) At first the kids were into all the early boy-band pop stuff like “She Loves You” and “Please Please Me”. Now they progressed to the weird John songs like “Strawberry Fields Forever”, “Lucy In The Sky With Diamonds” and “I Am the Walrus”. Michelle learned how to play “All Together Now” on the ukulele.

Dual Color Stellated Octahedron

Here’s an idea I’ve been working on for a while. I’ve seen this kind of thing done as modular and thought it was doable as a single sheet, and I figured I’d go for it. Single-sheet stellated polyhedra are pretty advanced, but the color change brings it to a whole ‘nuther level of complexity. It turns out to be a very rewarding shape to fold, and the design is replete with all kinds of interesting symmetries.

The first challenge was to work out how to achieve the arrangement of alternating colors. Once I’d worked that out the resulting (flat) shape would serve as the base for the 3-d phase. I needed two corners to come to the center like a blintz, but offset. Working out the amount of offset for the grid to be the right size was the key problem. It turns out the key angle is 67.5 degrees, which is 3/4 of 90 degrees and easily derived. It also turns out the angle has a slope of 3/2, which is also easily derived from a square grid. From this I was able to work out the arrangement of the squares in the inner rotated grid and the outer triangular grid areas, which correspond to the blintzed flaps. The 3/2 slope made was convenient because the grid is has an integer relation of the unit the whole. Each square of the grid has a length of 2/13 the edge of the paper, as you can see in the crease pattern. Neat, huh?

Another interesting property of the model is that once you’ve made the base and put in the color change squares, the easiest way to deal with the leftover paper on the two remaining corners is to flip the model over and do the same thing. The result is the pattern is the same on both sides, although made with opposite colors, and either side can be used for the outside.

The finished model fold together well and looks really good. I went ahead and made a few.

As an added bonus Lizzy and Michelle were folding bowls and picture frames, so here’s one.

Trouble with the Trees

The first part of March was pretty mild, but all that changed on Saturday. We had a major rain and wind storm that lasted the whole day and into the night. Trees fallen over and down power lines all over town, and lots of ‘em. All day long the trees out our window swayed menacingly, but we were pretty lucky. Every couple blocks a major tree is down, having blocked a road, taken out a power line, destroyed a car or damaged a house. I went for a walk Sunday and everywhere was the roar of chainsaws. Our whole yard is strewn with branches, our patio furniture, and a even few shingles off of our roof, and the neighbor’s yard is a pond. Today the kids had no school because the building had no electricity. Two days later and everyone is still getting back to normal.

My physical therapy was cancelled today because the clinic also was without power, but my back is improving. I’ve taken to pacing around the room during meetings at work, which seems to be tolerated. I’ve introduced some weights to my workout again, which feels good, even though it’s only about half the exercises (still have to avoid some kinds of movement) and about half the weight.

Promises of Spring

The weather has been really nice the last few days, with sunshine and temperatures getting up into the 50’s. Despite this there are still snow piles stubbornly clinging to existence. We had so much snow they haven’t completely melted yet. My back injury continues to improve slowly but steadily. I’m no longer doing my regular workout, just the exercises my physical therapist prescribed, plus plenty of walking. I’m hoping to reintroducing some parts from my regular workout this week. With luck I’ll be pretty much back to normal by the time the weather is good enough to start doing things outside.

Meanwhile I finished updating my Friends and Family photo galleries thru the fall and the holidays. This year I may have a few videos worth sharing, so look for that update soon. And as always, contact me if you need the password.

http://zingman.com/fotooz/
http://zingman.com/fotooz/2009-08/index.html
http://zingman.com/fotooz/2009-09/index.html