In the source article OP has linked elsewhre in these comments, the author notes that the first image is their own measurement and the second and third are David Chandler’s. I don’t know of Chandler myself but the article is clearly heabily inspired by him. I assume there was some kind of difference in methodology that produced the different values, like one of them was measuring the tape while it was un-tensioned and the other was doing geometry to get the length of the tensioned tape or something
The third image is noted to have a higher length (235mm) than the first image (233mm), however in the picture it’s clearly shorter.
Do I misunderstand the meaning of the numbers?
In the source article OP has linked elsewhre in these comments, the author notes that the first image is their own measurement and the second and third are David Chandler’s. I don’t know of Chandler myself but the article is clearly heabily inspired by him. I assume there was some kind of difference in methodology that produced the different values, like one of them was measuring the tape while it was un-tensioned and the other was doing geometry to get the length of the tensioned tape or something