Glasses Holder - wall mounted, stackable

I built this glasses holder for my wife who wanted a simple item to put her glasses (unfolded, which seems to be beneficial). It is intended to be wall mounted with a screw through the hole. To cover the screw a "screw cover" is available as well (might need scaling).

The holder has a spread of 15cm, which fits nicely for my wifes glasses (some centimeters left), but might be too small for glasses of bigger people. Scaling should be fine.

Several holders can be stacked on top of each other (which was a major requirement! :) ). It is recommended to leave some space between 2 holders (1cm - 2cm) to have enough space for each pair of glasses.