Post it Backing Board

Hello Folks, This is a mini backing board for post it.Technically its not a “design”. Am not a creative person at all. Its just a thin square that I made from tinkercad. The reason I made this because I had a lot of almost finished post it and when I put them in Stackable Post it note holder by 3Deste. I realized it is too soft to write. So that's why came up this backing board idea. It is nothing fancy but thinking anyone who doesn't have time to measure it, you can simply download the STL file and press the print button.