> Beautiful. Far more so than Python’s "stressed"[::-1]"

“stressed" [8..1]” Looks better, but IMO is worse, as it requires you to know the length of the string. Change the string and forget to update the indexing expression and you’ve got a (possibly silent) bug.

Having said that, Python IMO may be too powerful here, allowing, for example

   "abcdefghijklmnopqrstuvwxyz”[-5:10:-3]

   'vspm'

Makes perfect sense (from the fifth character from the end, step back 3 characters at a time until you reach the 10th character), but may be too cryptic for some.