New info on the lost "Clock Man" short from Pinwheel has recently been unearthed, you can check it out on the Lost Media Wiki thread listed below. Figured I'd post here in the hope that it jogs someone's memory.
http://lostmediawiki.com/Pinwheel_%22Clock_Man%22_short_(lost_animated_short;_1970s-1980s)
http://forums.lostmediawiki.com/thread/115/pinwheel-clock-animated-search-effort
http://i.imgur.com/eWplSWh.png
No offence but I've done a lot of research on Nickelodeon and I've never heard of this. And I'm one of the only people left who actually still post about '80's Nickelodeon so IDK where this came from but people always associate it to Pinwheel and it was never there. Maybe on another network around the same time but it wasn't on Pinwheel.
Ice
http://classic-nickelodeon-fan-blog.blogspot.com
Everyone who I have spoken to who remembers the short, remembers it being on Pinwheel (including Michael Karp, who, as you likely know, worked on the show).
Here are some videos on the subject that a friend and I recently made, please watch them before making up your mind:
https://www.youtube.com/watch?v=a_5Ab-GulqA
https://www.youtube.com/watch?v=TYCrGiUNc38
https://www.youtube.com/watch?v=jOZEd9Z4vjE
I know there's still no smoking gun proof of this thing, but I sincerely believe it exists and every lead points to Pinwheel.