So last week I completed my second and final week back at Stuy teaching CS. We spent Monday finishing up the mode lesson and then spent most of the week on this topic - writing a computer program to automatically decode something "encrypted" with a Caesar Cipher. The post I just linked to was from when I first taught the lesson. I've refined and reworked it considerable since then but the gist is the same.

This time, after running the cipher, we took a detour - I asked about what things they considered when purchasing a new laptop - they gave me all sorts of features like price, weight, screen size and more.

We then compared laptops by a single feature, say price, then two - maybe price and weight. This led to an x y graph - one axis price, the other weight. Ultimately this led to us normalizing the features (making them all within the same range) and then the distance formula which we can use in 2D, 3D or any higher dimension.

When everything was done, we were able to apply the distance formula to all the rotations of an encoded sentence and for each, compare the letter frequencies of the rotated sentence with the letter frequencies expected in an English sentence. The rotation closest to the expected frequencies was always the answer, provided that we had a long enough sentence to provide sufficient data.

We didn't get to build a completed program to do the decryption in class but we build some of the code, all of the key algorithms and did end up building the scaffolding needed - a subgoal labeled Python file.

That took us through Thursday. We probably could have completed the program if we continued on Friday but I thought that doing an AMA might be more fun and more valuable. After the weekend passed I did send along a finished program in case anyone wanted it and I encouraged them to write their own.

After my last class, I spent about an hour speaking with a few Stuy seniors and then I was off. This week, back to retirement with their regularly scheduled teacher back from grand jury duty.

I hope the kids had a good two weeks and got something out of the classes. I certainly enjoyed the time I spent with them.

Overall the in class vibe was similar to what I was used to, particularly if you allow for the fact that I was only in for two weeks so couldn't develop the same level of rapport with the students. I mean, I think I did okay - I was even gifted a mini lemon pie on my last day (3/14) which my me and my family promptly devoured later that evening. On the other hand, I was told by some Stuy faculty members that some things have changed - phone use, for instance is much more rampant with more kids glued to their devices when in the halls. In my classes, I had a few kids on devices or even on the computers doing non class stuff while in class but I didn't stress about it due to the nature of my time there. Also, it didn't necessarily mean the student wasn't engaged. I had one kid who kept playing a snake type game on the computer. Once, the person who was the official sub chastised her (I was unofficial, but that's another story). After class, I apologized to her and told her I didn't mind that she was on the computer doing something that I consider a modern day version of doodling. The reason was because she was actually always engaged - participating in discussion, completing assignments and in every respect, besides the "doodling" being an active engaged student.

I also, over the course of the two weeks got to meet a number of StuyCS seniors and had great informal conversations with a number of them. I'm going to save that though for a concluding post on my time back at Stuy.

As a final note, the CS and Math teachers were amazingly warm and welcoming - it was like I had never left, even with the people I had never met before. Likewise with the teachers I ran into from other departments.

On the other hand, one particular AP made for a much less smooth experience. Not the person in charge of the CS department - she was delightful and helpful, but rather the AP Admin. When I was first asked to do this, I said okay but the AP Admin said they couldn't hire me for a partial schedule of only 3 classes (rather than 5). That's false. Then other obstacles were thrown in the way. Apparently, he thought it better that the students receive no instruction rather than make the least effort to smooth the way. Finally, when it was okayed that I come in (on a volunteer basis), he refused to let me get a temporary ID which necessitated other people being inconvenienced daily to come and sign me in.

Now, had a decent AP Admin been at the helm, I would just have been hired part time. If something came up to make that impossible, they would have appealed to the PA or Alumni association for a modest honorarium and certainly they'd have given me the ability to come in without stealing precious time from some teacher on a non teaching period to sign me in.

So, those were my two weeks back as a teacher. It was weird to have to be at a specific place and time every day for two weeks - I had gotten used to the freedom of having no set time obligations but it was a fun two weeks.

No way I'll be going back full time, but if the StuyCS team needs me again, I'd be ready and able to pinch hit.