I was looking for an easy, lightweight C implementation of SHA-256, as a key derivation routine for elliptic curve cryptography. But apparently, the word "lightweight" is subject to horrible misuse. Hence, I just looked at the pseudocode at wikipedia, implemented it and ... it didn't work. Why? After 7 hours of bigendian nightmare, I compared my code to another implementation just to realize that the wikipedia pseudocode was wrong. Wikipedia should die. And yes, I corrected the wiki entry ... long live wikipedia!
I had a lot of fun reading the RTLO article in the GNY zIne and found myself very incompetent when it came to inputting that RTLO char anywhere. Hence, I wrote a little program that would set my clipboard to just the RTLO char, allowing me to paste it into browser forms and other stuff conveniently. I did this because the other tool that was linked isn't open source. Granted, my app has no GUI, but at least you can see its insides.