"I wonder how they're related?"

You could replace `id' with something that expands things, like \x -> (x,x):

    let f = \x -> (x,x) in (f.f.f.f.f.f) ()

Now it builds exponentially large tuple types. (?) And going back to the example in the blog:

    let f = \x -> (x,x) in (f.f.f.f.f.f) id

This is the same as the spacemanaki's example, without explicitly labeling the d1,d2,d3... intermediates.