The lambda calculus is a formal symbolic term rewrite system that has been used for many years both as a
mechanism for defining the semantics of programming languages, and as the basis for functional programming
languages. In this paper, we describe a completely visual representation for lambda expressions, VEX, that
has several advantages over traditional textual lambda calculus. Although VEX is designed as an
expression-oriented component of VIPR, it can also be used in teaching the concepts of lambda calculus as a
replacement for or augmentation to the teaching of traditional textual rewrite rules. Many semantic issues in
lambda calculus that are confusing to students, including substitution, free variables, and binding, become
apparent and explicit in VEX.