This model is based on hexagons with the flat sides measuring 25mm and the overall depth of the model is 113.2mm. You can print a single unit which has 6 hex compartments each, or glue them together to create larger storage units like the one pictured. FYI, cyanoacrylate/super glue is recommended for PLA and a polyurethane based glue like Gorilla glue works for PETG.

Feel free to play with the scale to suit your needs. You can also mix and match the whole compartment units with the divided ones to sort your collection more thoroughly. I found this inside depth (110mm) to work great for most all of my pen collection and each compartment holds around 8-12 pens or pencils each, depending on their size.