Side by side assumes that you would write the Clojure solution this way.

But that's not how I (nor, I imagine, any experienced Lisper) would do it. Lisp programmers are not afraid to write compilers in Lisp targeting Lisp. This is not something a Python programmer would consider doing.

I would implement Dan Friedman et al's Scheme constraint solver (cKanren) in Clojure (which can be done in a few hours) so I could solve all sorts of problems, not just Sudoku, in 80 lines of code instead of 200 with very good performance.