A visual formalism for functional composition is presented, which departs from many other visual systems in that it is not merely dataflow: the formalism also supports the notion of higher-order composition, i.e. treating functions as data. This is done through a simple notion of graph rewriting, which can be explained in a very intuitive fashion by moving software components along dataflow paths. The intended goal of this formalism is mainly didactical: some non-trivial aspects of the lambda calculus or other higher-order rewriting systems can be demonstrated without any mathematical background.