Here's the first few things that I had pinned:

https://www.moxfield.com/decks/Cl-d6bw1M0C-xrxQMPV-rw

🎼 The ni~ght we burned ol'Dixie down, and the bells were ringin'. 🎵

🎼 The ni~ght we burned ol'Dixie down, all the people were singin' 🎶

🎼Goin' 🎵Na~~🎶 na-na-na-na-na~🎶 na-na-na-na🎵 na-na-na-na-na~~🎶

I have a serious problem with Kuratowski's convention for ordered tuples. Specially, the ordered pair (0,0)={{0},{0,0}} ={{0},{0}} ={1,1} ={1}

I'm a mathematician; getting hung up on the minutae is my entire career. Noticing something that doesn't quite make sense and figuring out why my intuition doesn't match what I've been told is what makes me good at what I do. If there's anything about an explanation that doesn't make sense, I need to assume the entire thing is wrong until I can establish otherwise.