[zozbot234]

The untyped lambda calculus seems pretty uninteresting compared to 'typed' counterparts that tend to come with more interesting graphical visualizations out of the box, viz. string diagrams (where the topological features of the diagram have their counterpart in useful program transformations).

Also, I thought it would be fairly well established by now that the De Bruijn notation for the untyped lambda calculus, with prefix function abstraction but postfix application, better reflects its underlying properties since it allows for an intuitive visual understanding of reduction, where applications can be directly matched up to abstractions.