Focus on the number 31 above. The camera was directly above 31, so because of camera angle and perspective that is the only accurate place to look.
Recently I heard or read something about unreliable tape measures. Honestly, I can't remember where. Hey, it happened more than 2 seconds ago! It was either on Facebook or a podcast because that's where I learn all the important things PLUS (on Facebook) there are those cute cat vids. Friend of mine rescued a 3 week old abandoned kitten 4 weeks ago and she has been a faithful chronicler of its antics. Have I drifted off topic? Who knows, I started writing this more than 2 seconds ago.
Oh yes. Tape measures and important information. I'm a fan of Zede and Mallory Donahue, who have BOTH Facebook and podcasty presence. Check out Sewing Out Loud and the Self Sewn Wardrobe. It was probably here that I was alerted to the possibility that my tapes were wrong. But it could have been anywhere. See 2 second comments above.

So I lined a bunch of them up on my largest cutting mat, all starting at the zero point and held in place securely by a cast iron shoe last. I also laid a steel yardstick down. Fortunately the mat and the yardstick agreed, so I'm going to believe they are accurate. But just look at the tapes!
Frankly I am horrified by this. Devices that are designed to measure should measure ACCURATELY. Am I right? or am I right? Right?
I have never used cloth measuring tapes because I was told years ago that they would stretch over time, but I assumed I was fairly safe with the plastic ones. But notice that both of them (top 2) are too short.
And the flexible curve ruler that I bought just last week is a full 3/8" too long by the time you get out to 31 inches.
YOU HAVE BEEN WARNED!
********************
This public service announcement has been brought to you by DragonPoodle Studio, a completely not-for-profit private enterprise. The term "not-for-profit" is a description only and has no legal meaning or validity under the tax codes and laws. Not only is there no profit, it is pretty much a black hole into which a percentage of my disposable income regularly disappears. Happily, by the way.