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Julien Couvreur's programming blog and more

How round is your circle?

I found How round is your circle? a delightful blend of geometrical and engineering problems.
What I most appreciated is the historical perspective. It shows how problems arose from practical needs and curiosity, that their solutions were incremental, competed against one another, and were in many cases quite recent (less than a few centuries), and finally how those solutions enabled further discoveries and innovations. As a result of the specialization of knowledge and the accumulation of advanced tools, we can easily forget how simple things are actually not trivial at all.
Some highlights of the topics covered:

  • How to build a linkage that will draw a straight line?
  • How to mark graduations on the “first” ruler or sector (requires difficult angle divisions such as trisection)? A later chapter goes into the history and significance of slide rules with logarithmic and alternative scales.
  • How to draw a arc of a large circle (for instance to make a railroad curve)?
  • How to measure with precision (Vernier scales, magnifiers and fine-threaded screws)?
  • How to measure surface areas, and how planimeters work (tools to measure surfaces by drawing contours, surprising but effective)?
  • How to make shapes and volumes of constant width, and conversely how to measure departure from roundness (a hard problem)?

How round is your circle.jpg

Posture tips

Working on some simple and practical posture tips:

  1. Simply spreading your arms (as shown in the lotus zen pose) helps open your shoulders, reset your shoulder blades, and stack your head and spine. You can then bring your arms back to normal, but keep your shoulders open. You can do this any time during the day. Lotus zen pose

  2. Bring your portable device in front of your eyes (keeping shoulder and head posture described above), rather than your head down to your screen and slouching in.

Posture for using a cellphone

I remember first seeing this in a TED talk or some other video, but I can’t find the link anymore. Here are some more posture tips. Let me know how that works for you.

Cinderella review

I watched Kenneth Branagh’s Cinderella (Disney, 2015) last weekend and am curious to get the perspective of some parents.
I would definitely advise adult supervision and discussion for kids to watch this movie (as with previous versions of this tale and probably most other supposed kids movies).

Without going into the savior prince cliché, three observations of the kinds of poor choices and values uncritically displayed:

  1. The dad seems sensitive and reasonably smart, yet he brings people of awful quality (stepmother and two stepsisters) into his and his daughter’s life. That’s bad judgement. Strangely, Ella doesn’t seem to hold him responsible in any way.

  2. Ella decides to stay in an abusive situation, rather than find another job and home. That’s not courage. She obviously has many skills and is hard-working. Yet when a former maid offers to help find a better place, Ella argues that she loves the house and her parents did too. Clearly, her parents did not communicate proper priorities (daughter’s well-being first, house distant second).

  3. Ella ends up forgiving the stepmother. That is not kindness, but perpetuating the abuse. Excusing and showing empathy towards a sociopath means the sociopath wins and has power of you. The stepmother not only has caused a lot of harm, there was no indication that she recognized it or felt sorry. So, Ella’s forgiveness of persistent evil raises the question of whether she will remain alert and able to protect herself in the future.

It’s important to recognize when the two virtues promoted in the story (courage and kindness) are being manipulated and distorted to allow for abuse to continue. Such confusion is what allows abuse in the first place.

Cinderella movie poster