This is a Ikea Variera separator (organizer) for 4 compartments. Helps you neatly store your forks, knives, spoons and etc.
The separator walls can be made out of any sheet material 2-mm thick (i started from carton and ended up with acrylics).
The easiest way (which worked for me) to glue in the ribs was attaching them to the cut out sheet parts applying some super glue, and then inserting into the container.
The author marked this model as their own original creation.