This is a foldable 40 centimetre ruler.
you will need a relatively large print bed to make this. I used an Ender 3 V2 , with 220 by 220 by 250 mm print volume, and it barely fit with the skirt. This has a 0.4 mm tolerance, which worked for me, but i will soon upload more models with different tolerances when I can.
Warning: Do not print with raft or brim (I hope you know that by now) And turn it 45 degrees to make it fit if it doesn't

P.S. pls print with max 0.16mm layer height. I tried.

(yes i really did print it 22 times.)

Creality

Ender 3

No

No

200

20

Dont use unbranded filament like me :D