Unlike on other Stack Exchange sites, the execution of an idea really makes a difference on this site. My question is, if an idea for a challenge has been used before, does that make any other challenge based on the same idea off-topic, or can an idea be re-used if it's implemented in a substantially different way?
I ask because I recently wrote a challenge based on an idea that turned out to have been used before. I didn't realise this until I pasted it into the site, but I decided to post my question anyway because the execution of the idea is very different, and the kind of answers I hope to attract are very different from the answers to the old question. (The new question is really designed to allow quite long answers that catch a lot of special cases, whereas the old one has a scoring system that very strongly favours short answers.)
There is some (very reasonable) debate in the comments as to whether my question is a duplicate or not. I would like to know what the community thinks, both about this case and about the general question.
My new question: Turn nouns into plurals
The old question: Pluralize it!