Its known to hold:
I modeled it on bottles from Beetles, Imtiti, and Cheeka.
It is modeled in OpenScad. The (poorly written) scad file is included for customization should you wish to do so. It is somewhat parametric.
I've included two STLs, one that is 4x4 and the other is 5x5. There is a 6x6 in the SCAD file, but I didn't want to wait for it to render. I've printed the 4x4 version.
The author marked this model as their own original creation.