Since c++23 supports attributes on lambdas, @lefticus came up with this real beautiful snippet of C++.

cpp_syntax_is_great.cpp

///
/// Valid syntax for whatever reason :D.
/// See https://www.youtube.com/watch?v=YlmxNJnone0 for details (if you dare).
///

int main() {
  auto l = [][[]]([[]] auto) [[]]  { return 42; };
}