Excellent music synchronization. I was going to post a joking comment about incorrect polarity... oof, not fun but good it'll be a fairly easy fix. Definitely worth watching in reverse, although somewhat less productive I suppose. 

at first it looks like you're putting them back :D hand soldering 110 LEDs was tough, this is madness :) It's also "good" to see that someone else can solder LEDs the wrong way. That's a 50-50 thing that happens to me more than I want :)

Yeah, there were so many distractions with setting up the video, then considering where I'd stop for the day (I had intended to only mount some of them yesterday, then come back to it later), and all the rest.  The few seconds of thought I gave to which end should go where got me the wrong answer.  Maybe I should only make square arrays, where it doesn't matter :-)

Kudos!

How did you make sure they are oriented properly?

There's a little green cathode mark on one end.  I can't see the mark clearly with the naked eye, but can tell that one end looks a little darker than the other - that's enough to tell the difference.  After placing them all, I checked with 10x magnification to make sure they were all good, then put them on the skillet.  Here they are close-up:

I see. The ones I have have the spot on the underside, which is not nearly as convenient.

I wonder if there is a little jig that you could make (or print) to hold the tape they come on - it holds the black side down and lets you peel away the clear, advancing as you go - maybe with a little lever (or servo) to advance to the next LED.  If you could fit tweezers into the tape recess, it would make the whole process easier - they would always be oriented correctly - and right-side-up!

Make a LED extruder for your 3d printer :D

That is a fantastic video, Do not think my eyes and hands could handle that :-)

Outstanding Lol, love the video... :-)

easy!