However, seriously, clojure looks really interesting, being a cool language on the JVM and being purely functional. But does anybody know if it is possible in this language to make (easily) funny structures like circular lists, graphs, etc. ? AFAIK, that's the problem when you don't want to use set-car & set-cdr in Scheme (that's a problem in NewLisp too, for example) : you loose them. Did clojure manage to overcome this problem ?