I was playing with corrugated cardboard today gluing strips together to replace a chewed up cat scratcher. I noticed how cool it was to look through the corrugations of a strip and move it around. Then I wondered what it would look like to precisely alter the angle of pieces of cardboard in a stack.
So I made this: 3" circles with a 1/2" hole rotated 10 degrees between each one.
Slid all of those onto a half inch square tube and slowly rotated. It has a definite lava lamp quality.
Very interesting trick! 
Is that a grill rotisserie rod? Mesmerizing!
No, just steel tube. I did try using my rotisserie motor to spin it smoothly. But it was so slow it removed the magic.
Your cat is one lucky pet!
Really cool effect!
let us know how the cat likes it. I might make a couple of these for ours 
Great idea!
I like it! Interesting possibilities!
I love stumbling onto that kind of serendipity.
Man, that’s cool.
I love pretty things made on the Glowforge; but I also really like experiments… hey, what would this look like?
I love the inquisitive mind fed by a laser.
Well done, inquisitive mind.
great, now my kitties want custom cat toys! lol
(adds it to the list)
