I just went back to check whether I have a sandbox on Wikipedia. Turns out I do: https://en.wikipedia.org/wiki/User:Susam_Pal/sandbox

I am not a regular contributor to Wikipedia but the little time I have spent contributing there has exposed me to its very elaborate culture, with barnstars being one artefact of that culture, alongside policy acronyms everyone seems to know by heart, WikiProjects organised around every imaginable topic, userboxes that are little badges that say something about you, etc.

By the way, I added a few userboxes for the Logo programming language, in case there are any Wikipedians out here who happen to love Logo: https://en.wikipedia.org/wiki/Category:User_logo