I agree that the “Newton’s Swingset Cradle” seems very familiar, but I was not able to find it in a CIDU post; it may have been embedded somewhere in a comment. I did find one dated 25-Apr-2011 by Zachary Kanin, but I’m not sure whether it is the one we saw before:
There’s plenty of versions of it, such as a version that someone put on a pillow and sold on Amazon. Usually with the subtitle, “Why science teachers shouldn’t be given playground duty,” or something along those lines. (Not that a lot of schools that have playground duty have dedicated science teachers….)
Hah! I’d buy that pillow, except that my wife would have kittens over it.
This is over a month late, but I just happened to discover a pair of relevant cradles at Andertoons. Here’s one (#8123):
P.P.S. Neither one of those Andertoons cradles has ever appeared in a CIDU post (there’s no way to tell whether one might have been embedded in a comment).
Comics I Don't Understand 
I agree that the “Newton’s Swingset Cradle” seems very familiar, but I was not able to find it in a CIDU post; it may have been embedded somewhere in a comment. I did find one dated 25-Apr-2011 by Zachary Kanin, but I’m not sure whether it is the one we saw before:
There’s plenty of versions of it, such as a version that someone put on a pillow and sold on Amazon. Usually with the subtitle, “Why science teachers shouldn’t be given playground duty,” or something along those lines. (Not that a lot of schools that have playground duty have dedicated science teachers….)
Hah! I’d buy that pillow, except that my wife would have kittens over it.
This is over a month late, but I just happened to discover a pair of relevant cradles at Andertoons. Here’s one (#8123):
P.S. Here’s the other one (#9057):
P.P.S. Neither one of those Andertoons cradles has ever appeared in a CIDU post (there’s no way to tell whether one might have been embedded in a comment).
Here’s another one from Dark Side of the Horse (9-Mar-2020):