>>1
Try Nanochan.
https://textboard.org/prog/6/77,78
That is the Lua version, which is a simple imageboard implemented in less than 3500 lines of Lua. For some reason, they have since ported the code to C++. It looks something like this http://nanochanqzaytwlydykbg5nxkgyjxk3zsrctxuoxdmbx5jbh2ydyprid.onion
If Nanochan is down, refer to Picochan, which started as a clone of Nanochan. It has similar look, feel, and functionality to Nanochan. Picochan: http://picochanwvqfa2xsrfzlul4x4aqtog2eljll5qnj5iagpbhx2vmfqnid.onion
Picochan's source code can be found at https://github.com/vxiiduu/picochan