By the way, why do you need a backslash to define a lambda? Apparently it doesn't give any additional information. All you need to know that's a lambda is the presence of the -> operator. Is that a way to make the compiler faster?
\x \y x + y
\x \y \z x z (y z)
Cassette looks really nice - great intro page, and a great name too! Making something simple is much harder and more valuable than making something complicated.