I use this to organize our markers for our whiteboard calendar.
I designed this in Onshape. All of the models I done in Onshape have had issues scaling when sliced. If needed, just scale the model 2540% to switch from mm to inches.
For printing, I used PLA+ and printed standing up with tree supports. This worked great as long as I printed slowly.
The author marked this model as their own original creation.