I can't find it, but I've whipped up something better. This example recursively loops through the decoded JSON object. Some notes:
1) The current key (e.g., "firstName") and its corresponding value (e.g., "John") are accessible via two string Attributes.
2) This example requires code blocks and use a non-global custom block.
3) The actual iteration of a JSON object occurs in a random order. Any ordering you wanted to ensure would have to be included in the data itself and would have to be sorted after the fact, as might be important in the sentence example you give (e.g., "word index: 1", "word index: 2").
Hopefully this will be a good start for you.