Related: There exists programming language Unlambda https://en.wikipedia.org/wiki/Unlambda https://en.wikipedia.org/wiki/Unlambda which is based on combinatory

Related: There exists programming language Unlambda https://en.wikipedia.org/wiki/Unlambda https://en.wikipedia.org/wiki/Unlambda which is based on combinatory logic in which "Variables are unsupported". From a programmer's viewpoint it seems like a daunting task: Write all your programs without using variables. Can that work in practice?