the sequence of satipatthana recapitualtes the catuskoti:
observing the body internally
observing the body externally (not internal)
observing both the internal and external bodies
observing feeling internally (feeling is neither the internal body nor the external body)
externally (not internally)
both internally and externally
the mind internally (being neither internal feeling nor external feeling)
the mind externally (not)
both
dhammas (being neither)
I think this is a fascinating example of how deeply embedded the tetralemma or catuskoti is embedded in much of buddhism, even where we least expect it.