OpenID Support

Back in 2003, I worked with a team of programmers around TWU to consolidate all our passwords into a single sign-on system we called TWU Pass - the idea was that everyone at TWU should only need one password to access anything on the web.

Five years later, I'm excited to announce that TWU Pass now has OpenID support, which means that

1. Everyone with a TWU Pass account can now sign in to thousands of other websites without a new password!
2. You can use OpenID accounts from Yahoo, WordPress, LiveJournal, Blogger, AOL, and dozens of other providers to sign in to TWU Pass instead of using your regular TWU Pass password.

What this boils down to: fewer passwords to remember.

For technical folks, we're running OpenID 2.0, so we get a lot of neat benefits, such as being able to sign in with "twu.ca" rather than needing a full OpenID URL.

This post is a little different than some of my previous ones.

I read tonight that Microsoft's latest service pack for Microsoft Office now supports ODF, the format used by OpenOffice and other (especially open-source) word processors. It might seem a little trivial, but this give me several better feelings about the Office strategy. I may be wrong, but I had the sense that MS was fighting ODF (and in a sense, the open-source projects it represents) with their version of OOXML, sort of an XMLified version of their binary formats, and this is the first major step I've seen toward coming back to the table as competitors and not monopolists. The word that came to mind was "repentance." Perhaps not in the moral sense, but in the business sense: a change of strategy.

This lead me to think about my response - positive feelings for this move - and ask "Why does that make me think more highly of MS?" The conclusion I came to is that a company that's willing to repent, to change course, strikes me as one that is able to swallow pride when appropriate and do the right thing.

Which lead me to my second thought - that's what Agile development is all about. It's about being very ready to change course, admitting that we can go in the wrong direction, and making sure we don't let pride, ignorance, or anything else get in the way of doing the right thing.

A fairly well known pastor recently described repentance as a critical part of being a Christian. "Dogs bark; Christians repent." Perhaps repentance is something we're looking for more of as a society - from businesses, teams, and individuals. It's certainly hit me as an unexpected intersection of life and faith.

So after lunch today I was hanging out with my 2.5-year-old, playing with the wooden trains. (In case you're wondering, I telecommute and yeah, I've liked trains my whole life.) Instead of the usual oval shape, we decided to build a really long train and to try to make a mountain - a "purple mountain" as Seth put it.

So, after realizing we had no purple construction paper, I set out to make one from a standard letter-size piece of paper. I attempted to make the largest cone possible, and after some tinkering with the paper, some of my (under-stimulated, minimal) math juices started to flow and I realized that I had a maximization problem. Certainly not one that requires University-level math, but still...

So the question was, what's the bigest (largest volume) cone I could make from an 8.5x11 piece of paper?

As I played with the cone shape in my hands, Seth pointed out that it was a "triangle" and I pointed out it was a "circle" at the same time. (He ran to get his circular and triangular blocks to compare.)

The volume of a cone depends on its base area and height: (1/3)hπr², but really, in this scenario, we can remove one of those variables, because a tall or flat cone would obviously have less volume and because of the shape of the paper, the most efficient way to use it would be to inscribe a half-circle into it and use that, right? So that's what I did:

That's the mountain I made with Seth.

Second thoughts

Later, I realized I could have actually made it a little bit bigger by using a different shape and actually maximizing both r and h. If I had moved the centre of the circle closer to the middle of the page (so that the circle touches the top), I could have cut a "pie shape" (wider than 50%) that would have produced a taller height on the cone while maintaining the surface area on the bottom. I think that would be the largest cone you could make with the paper since that would have the widest radius and the tallest height after maximizing the radius. If you think of something bigger, send me a note on Twitter (oifland).

Third thoughts

Actually, the radius of the circle ≠ radius of the cone at the bottom - this last design actually increases the radius of the cone.

The radius of the bottom of the cone = the length of the arc cut from the paper divided by 2π. The arc length could be determined with some calculus and trig using the triangle at the bottom of the page. Despite this realization, I still think that this would be the biggest cone possible.