- the extended solution to this exercise can employ a slice (returns a copy) instead of calling `.copy()`. [matrix](../exercise-concepts/matrix.md)
- a slice within an iterable, i.e. the slice of items from `<iterable>[x]` to `<iterable>[y]`, can be accessed via `<iterable>[x:y]` notation; a third parameter allows "skipping" by `z`, i.e. `stringname[x:y:z]` [phone-number](../exercise-concepts/phone-number.md)
- because `str` in Python is a sequence type, [slicing](https://docs.python.org/3/reference/expressions.html#slicings) syntax can be used here. Specifically: for syntax `string[start:stop:stride]`: [reverse-string](../exercise-concepts/reverse-string.md)
