31. December 2025

Bryan Byun

Bryan Byun passed away recently. His cause of death was an aggressive cancer. His birthday was today, December 31. I think he would have been about 55 or 56.

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01. October 2025

Hue shifting when you have to work in RGB

I work on the web and usually have access to CSS color, which lets you specify colors in the HSL (hue, saturation, lightness) space. That makes it easy to shift a color to make it redder by nudging the H value toward 0 or to send it closer to purple by moving it toward 360.

Recently, I needed to shift hue in GLSL, and which doesn’t have HSL. You only get the RGB (red, green, blue) color space. Fortunately, on a previous blog, I had written a post about hue shifting in RGB. I relearned how to do it from that.

So, I’m reproducing the original 2010 post here with added commentary. If you don’t want to read about how this works and just want to mess with a spectrum, here is my new tool for doing that.

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16. September 2025

An open letter about AI grading children's essays

I learned via this report that the essays in the MCAS are being graded with AI, and that it has graded at least 1,400 essays incorrectly. And that is only the grading that was obviously wrong and discoverable. There are likely more undiscovered critical mistakes.

It is unsettling that my kid’s essays and other kids’ essay are being evaluated by models that have no real understanding of writing. They use statistical methods to find correlations between sequences of symbols and past scores, without understanding anything. This punishes individuality in addition to just plain not working.

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