Hyperbolic crochet

You never know what you’ll learn at the library!

Recently, the Corvallis-Benton County Public Library began hosting a monthly Fiber Arts Meetup, which is culminating next weekend (Nov. 18) with a Coral Reef Community Art Collaboration. Although there are many kinds of relevant crafts and projects, one that was featured was hyperbolic crochet. Rather than being an exaggerated form of crochet, this is the process of creating “negatively curved” surfaces. This is a word for a surface that curves in two directions away from what is “flat” (tangent), like a saddle (bending down on your left and right, and up in the front and back). A positively curved surface bends only in one direction, like when you’re on top of a mountain looking down on all sides. A surface with zero curvature would be infinitely flat in all directions.

You can play with this in crochet. If you crochet a doily or a potholder, that generally would have zero curvature. But if you wedge in extra stitches so that they simply cannot lie flat, you’re going to generate a curved surface. The method I learned for hyperbolic crochet simply has you doubling the number of stitches in each hole as you go around, an exponential growth that creates a very organic-looking ruffled structure:

And because yarn (and knitting) is flexible, the same shape can shift into another 3D configuration where the negative curvature is even more evident:

It is surprisingly fun to play with this object and feel how it moves and shifts. What you can’t do is make it lie flat, at least in our three-dimensional world. Each row has twice as much length within it as the previous one. Such a fascinating construction! Thank you, Mari Beth, for teaching me!

Human organs … on a chip?!

Recently I learned that we can actually grow miniature human organs in a tiny, nutrient-rich environment and keep them alive. This has all sorts of useful applications such as testing the safety of new drugs here on Earth or assessing the impact of radiation on human tissues in space. In fact, the tissues can even be grown from a particular person’s stem cells and then multiple tiny organs connected together so that systemic effects can also be studied. Apparently while I wasn’t looking, this bit of science fiction became reality!

A few days later, I had a thoroughly unexpected moment of convergence. I was visiting the Evergreen Air and Space Museum and marveling at, among other things, their full size model of the Spirit of St. Louis. While reading the poster about Charles Lindbergh, I learned that among his many interests and activities, in 1935 he also invented a perfusion pump – a device meant to keep organs alive outside the human body by artificially circulating oxygen and nutrients (and keeping out infection). (The picture at right is credited to Georgetown University.) I’m sure he’d be thrilled to see the latest advances, less than a hundred years later.

A curious mind can be applied to solve all sorts of problems!

Moonshot programming

This iconic image shows Margaret Hamilton standing next to a printout of the flight software that she and her team wrote to control the Apollo Guidance Computer. I recently discovered that the code has been made available via a scan of the printouts, later re-typed as code, and uploaded to GitHub. The code is written in assembly, which consists of individual instructions to load, calculate, and act on data values. Today we use compilers so we can write code in higher-level languages that are easily understandable by humans, but at the time compilers were still pretty new, and the available memory was so limited that they wanted humans to do the optimization at the individual instruction level. Wow!

Here’s an example excerpt from the code. Even if you don’t know AGC assembly (I don’t), it’s possible to follow along due to the excellent comments.

I’m in awe of how this massive software engineering project would have proceeded (How did they test it? And without modern version control… did they use periodic printouts in case they found a mistake and wanted to roll back?) What an inspiring project!

Browsing the open issues on the project, they seem dedicated to increasing the quality of the content by carefully proofreading it against the original scans of the code printouts. What a labor of love :) But what a wonderful piece of programming history!

Helping wasps go to a better place

The other day, I discovered an enormous wasp nest (about 14″ in diameter) in a tree next to my house:

The next morning, Google helped me discover Dan Scollard, who comes out to remove wasps from homes, humanely “sends them to sleep” in a cooler full of dry ice, then donates them to a lab that extracts the venom for use in allergy shots. (!)

When he arrived, he said, “Oh, that’s a beauty. A lot of people say they found a nest as big as a basketball, but yours actually IS.”

My nest was constructed and occupied by the bald-faced hornet (which apparently is actually a wasp). Dan told me all about this wasp; he has a real admiration for them. I highly recommend reading about their life cycle and also viewing Dan’s photo gallery! These wasps are a useful part of nature, but risky to have next to your door where you (or unwitting visitors) could be suddenly attacked. Apparently this wasp can be quite aggressive and territorial.

Dan put on all of his gear, then vacuumed up all of the wasps around the nest, waited a bit for more wasps to come home from hunting, did a second vacuuming pass, and clipped the nest from the branch to remove it. He said it would hang it in his backyard so the queen (who had not emerged) could “live out the rest of her days in peace.” He said I could hold the nest with its lurking queen: gosh wow!

Me holding a wasp nest

What an amazing experience! It’s a joy to meet knowledgeable people who love their subject and use their knowledge to do good in the world. I’m much happier sending these wasps out to help people avoid severe reactions, and the process was so much better than dousing the nest with poison. Thank you, Dan!

Flying IFR to Aurora

On May 27, I flew with friends up to the Aurora State Airport (KUAO) for a safety seminar. It’s about a 30-minute flight each way. I’ve never actually visited the town of Aurora on the ground, but I’ve flown to the airport many times. Willamette Aviation does a wonderful job of bringing in great speakers and also serving treats like ice cream and pie – and for this event, a full BBQ!

By default, we planned to fly there VFR (visually). But when we gathered at the airport, the cloud ceiling was only 1500′ above the surface. No worries, perfect chance to exercise that instrument rating! We had five people going in two planes, with one instrument-rated pilot per plane. I filed KCVO DUBMY KUAO to set myself up for the RNAV 35 approach to KUAO, but ATC came back with KCVO CVO V495 UBG KUAO at 6000′, a longer route that would take us north before coming back south to make a northward landing. I hoped they might give us a shortcut along the way.

I was flying the slower of our two planes, so the faster one departed first and then we “held for release” until they were clear of the airspace and Cascade Departure cleared us to take off. The clouds were now at 1900′ above the ground. We climbed up via the SHEDD4 departure, punched through the clouds (which were only a few hundred feet thick) and then were on our way north. The clouds below us got thinner and I had this beautiful view:

Our lead plane was vectored off of V495 with the hoped-for shortcut to the RNAV 35 approach to KUAO. We were left tracking V495 much longer, but our vector finally came and we got to head over to execute the same approach. After joining the final approach course, we punched down through a thicker cloud layer, then executed a nice landing.

The seminar was about “continuation bias” and how it can lead to many bad outcomes, including CFIT (controlled flight into terrain). Here’s a nice summary of the high points along with great tips.

Afterwards we enjoyed the BBQ and then prepared for the return flight, which was also IFR. We had a lot of sunshine, and the clouds were higher (around 3500′), but we still got to plunge into and out of them. There is really nothing like that feeling – it is a thrill every single time!

One of the great things about flying this day were my companions! I had a great co-pilot who is working on his instrument rating and handled our ATC communications for practice (with me monitoring of course, since I’m responsible for the flight in this setting). I really enjoy flying as a team! We also had a passenger in the back taking his very first flight in a small plane. He took a lot of pictures and seemed to enjoy the thrill of ducking in and out of clouds too!

Looking forward as we returned southbound, above the clouds at 5000′:

Looking out to the side:

We returned to KCVO via the ILS 17 approach from SKIVE (a new waypoint for which apparently some folks say “skive” and others say “skeevy”). Once down through the clouds, we canceled IFR and crossed over midfield to land on runway 28.

One of the challenges of this flight was that with three people in the plane, it was near max gross weight. I did extra-careful fuel calculations and we were able to go with half-full tanks, but even so the plane’s performance in terms of climb rate and cruise speed was definitely lower than usual. However, it was a great flight, and I just love getting to sail through the clouds and maintain proficiency with instrument flight. Looking forward to next time already!

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