However, there exist some dissimilarities between both languages implementation of scoping. These earlier Lisps implemented lexical scoping in the compiler and dynamic scoping in the interpreter. Implementations of Common LISP were thus required to have lexical scoping. Common Lisp requires that both the interpreter and compiler use lexical scoping by default. Modern versions allow nested lexical scoping. This project started in November 2018, with NZ$2m of initial scoping work. ARB is currently in the process of updating the Scoping Plan. The first phase of the product development process is scoping. ISLISP has lexical scoping for ordinary variables. Delegation can also be used to implement features such as namespaces and lexical scoping. Common Lisp also borrowed certain features from Scheme such as lexical scoping and lexical closures. Free variable values are found using static lexical scoping. Variables are weakly typed and dynamic with no scoping rules. Common Lisp adopted lexical scoping from Scheme, as did Clojure. Dynamic scoping is fairly easy to implement.