WALL, sorry for not doing the topic justice, not good at explaining@kitten not sure how to describe so may be off, its essentially a way to declaratively represent tree of values through simple lists, not far off from an xml in a way i guess something like (val1 val2 (val3 val4 val5) (val6)) the interesting thing lisp then actually makes it so these lists can act as executable code funny example: (+ 1 (* 2 3)) (which you can treat as 1 + 2*3) then you can treat these like lists in any other language, construct and append dynamically and eval them, big reason why lisps are metaprogramming machines it isnt too far off from direct ast manipulation as well, lisp only language where i respect calling (eval x) i have no idea if that was clear in any way...