@Mark_Kriegsman 's 100-line demo reel is the gift that keeps on giving!
I ran it on a high-density strip attached to my ceiling fan and the results were incredible, especially when combined with long-exposure photography.
I made a video about it here: https://youtu.be/pv3lkLQSP68. There’s a link in the video description to a Google Drive folder with dozens more images 
Beautiful. What a cool idea.
@marmil Thanks! Was the pun intended? 
Really nice !! How many leds/meter ?
I watched this in bed, looking up at my ceiling fan… my wife jabbed me and said ‘NO!’.
There’s always the spare room
@Yves_BAZIN Thanks It was half a metre of 144/m strip (so 72 LEDs in total). I’m sure you could get a neat effect with lower density strips as well.
@Mike_Thornbury Do it! 
Just be careful you don’t make the fan too unbalanced and wreck it haha. I made sure to get as much of the weight as possible close to the mounting bracket of the fan blade.
@Chris_Parton LOL - having spent weeks balancing fans over the years, I’m confident I wont end up ripping the thing from the ceiling with unbalanced forces big coins and gaffa tape is the answer!
@Mike_Thornbury have the fan write lI love you’ from time to time
If it was a fan with 4 or 6 blades, two strips on opposite blades would help balance things. One of the strips could be shifted in/out by half the pixel spacing so that the swept arcs of the two strips went in between each other to double the resolution.
@marmil That’s definitely a worthwhile consideration. It would increase the persistence of vision effect, so it would look more like my photos to the naked eye. I would have wired up two blades, but I only had the once length of high-density LED strip
@Mike_Thornbury Sounds like you’re the right man for the job then!
@Chris_Parton Im not sure my wife would agree - although I did ponder a solution…
ESP8266, 240V>5V transformer being fed by the fan main supply, running as an Apple Homekit device…
I still can’t see her letting me do it… 
@Mike_Thornbury Interesting. I can’t see how you’d have the LED strip on a fan blade and have it powered by the fan supply without running a cable that would quickly wrap itself around the fan motor. Some kind of brush system?
@Chris_Parton A slip ring would need to be used.
Yes, exactly that. You only need a 5v feed, it can be simple. For continuity, a battery could ensure that and supply glitches don’t end up rebooting the system,
Nice. I have done a lot of playing around with spinning objects and LEDs. The ESP32 makes it easy to run the motor at whatever speed you want while changing the LED patterns. I found that no video or image really captured the moire patterns that result from the LED refresh rate and the rotating object. At some speeds there are patterns that move in the opposite direction from the rotation.
Yeah, agreed, demoreel is awesome. Great way to see nice bits of the FastLED API.
@Steve_Anken That looks awesome! I’m hunting down a spare ceiling fan motor to use for some other light painting experiments.
@marmil Thanks for the info, looks like it’d do the trick!
Thank you @Mark_Kriegsman for demoreel100, I just tried it out on my matrix for fun, and confetti, sinelon, and jungle look surprisingly good on it
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@Marc_MERLIN did you confirm it as a matrix or just as a light string?
@Mike_Thornbury I’m not sure if I quite understand your question. FastLED does not know whether you have a matrix or not, I simply gave the matrix as a light string, and got what you see in the video.
