In the recent week the Blender community became crazy on the particular geonodes hack, that allows you to create a simulation in Geometry Nodes alone:

[![1] NENGHUO on Youtube: Breakthrough! !" For Loop" in the blender geometry nodes.][2]

[![3] GifCo on Twitter: Geonode simulations are all the rage these days!!][4]

[![1] Default Cube on Youtube: FINALLY! NEW Loop Node][5]

[![1] Seanterelle on Youtube: Geometry Nodes Differential Growth Simulation Tutorial][6]

This is not a forum to vent one's frustration, so let me just say a better¹ technique exists at least since I started using GN in Blender 3.0, so I decided to share, in Q&A fashion. Everyone is welcome to post his alternative technique - perhaps one involving physics - I've done something very limited in geonodes+cloth here:

[![7] Create Curve from Path of an Object Using Geometry Nodes][8]

¹ - Maybe some people hate Python so much, they would rather use a dirty hack relying on Blender failing to protect from circular reference, which can hang the program, is not officially supported, is not a designed feature: exists in memory only as a temporary evaluated object without any representation in .blend datablocks, therefore can't be saved or maybe even restored with <kbd>✲ Ctrl</kbd><kbd>Z</kbd> undo [not sure, haven't tested], runs an erratic number of times (I think on each depsgraph update?) and so runs in a single frame rather than with one step (or a fixed number of substeps) per frame, and can stop working (be fixed) in future versions of Blender. 

  [1]: https://i.sstatic.net/usbhO.png
  [2]: https://www.youtube.com/watch?v=By4wsOR7DVA
  [3]: https://i.sstatic.net/4Ruzj.png
  [4]: https://twitter.com/giffboake/status/1591822933495775236
  [5]: https://www.youtube.com/watch?v=-gIk_ZH4ySE
  [6]: https://www.youtube.com/watch?v=zMODkMdc8Ec
  [7]: https://i.sstatic.net/uMen5.png
  [8]: https://blender.stackexchange.com/a/276261/60486