This is a goofy and or fun beginner exercise to see how call-with-current-continuation and dynamic-wind? can interact in a rather displeasing manner. What happens when you run this in the REPL? What happens when you try and break?
(let loop () (call-with-current-continuation (lambda (k) (dynamic-wind (lambda () #t) (lambda () (let loop () (loop))) k))) (loop))
Note: According to R5RS,
The effect of using a captured continuation to enter or exit the dynamic extent of a call to before or after is undefined. (Those procedures are the first & third arguments, respectively.)