Here is one that is efficient since it is only wireframe (sketches). It also cannot be trimmed to a cube...
But I can nest this to a 25x matrix without issues.
Now try something with the attached file.
Change the relation "matrix" to 20; regen; change matrix back to 1; regen; save. Look at the file size difference! The idea is that you really don't want to save the file if you ever generate the large version. The 25x matrix file went from 1.2Mb to 53mb even though it was only the single cell at the time of save.