McCarthy Math
habs.sdf.org
habs.sdf.org
I find it interesting that the original LISP had commas between list entries, while all "real" LISPs use spaces.
I also like how they introduce lists straight away, rather that starting with pairs and constructing lists from that. I always found that to be a distracting detail. Yes, it highlights the simplicity: You don't need lists, all we need is pairs! But even that is not true: You don't even need pairs, because you can construct them from plain, primitive functions.
However, I find it strange that all examples are long strings. Nobody reads LISP code that way. Proper indentation would help a lot with readability. In particular, the similarity with the provided Python samples would become more apparent.
So awkward and unintuitive.