While programming and listening to music, I had this habbit of moving multiline cursors back-and-forth. Since code lines have different widths, it used to look like a music visualizer in my imagination. So, I turned that into a VSCode extension.
Demo video: https://www.youtube.com/watch?v=WM2GeKBBX5E
Disclosure: While I've been obsessed with audio visualiser from the start of my programming days and built one in Processing and another in C++/OpenGL from scratch, this one was partially vibe coded.