Most people have difficulty with the fact that an array expression can very compactly represent some powerful functions. For example, (+/*)\: is matrix mult

Most people have difficulty with the fact that an array expression can very compactly represent some powerful functions. For example, (+/*)\: is matrix multiplication. The following computes the transitive closure of a binary relation (represented as a boolean square matrix): {x|x(|/&)\:x} Its core has a similar "shape" as matrix multiplication: (|/&)\: So in a sense variable names don't matter all that much! To grok this code you have to stop thinking in terms of item at a time operations and start thinking of operations over collection of items. If you know how to write unix shell pipelines you are already somewhat familiar with this paradigm except that a shell doesn't provide most of the more useful features of array languages!