Well, "hoax" may indeed not be the best word, because it implies intent. I've known of another highly intelligent software developer that invented similar symbology, but was suffering from a mental disorder which made him believe his work was useful even though it's only uses were 'self-referential'. Highly intelligent people, including software developers, are not immune from such disorders.
Y Combinator is the simple syntax for representing the concept of passing a function to itself, so it's useful, for symbolic manipulation.
However the "Tree Calculus", just from those 5 little rules, is supposedly able to do all kinds of magic. I'm not buying it. It's nothing but musings and examples of binary trees, and how you can convert various data structures to binary trees.
