This is an insert for IKEA's KALLAX. The height can be adjusted in 2 cm increments, and the depth of the shelves is flexible, allowing for a stepped arrangement. It is ideal for organizing miniature figures, A3 drawing paper, and other items according to your preference.

Please note that assembly can be somewhat challenging. The support columns are joined using a wedge joint, so when hammering them into place, be sure to control the direction of movement and carefully check the fit as you work.
As shown in the reference photos, where a cardboard box is used for support, press down firmly while striking with the hammer from the same directional surface.
Slide the triangular part of the dovetail joint into the corresponding groove of the mating part. When doing this, take into account the offset of the shallow interlocking section and fit only the triangular part first. The initial insertion can be done with hand pressure, but after that, apply pressure while hammering it in parallel to ensure a secure fit. It is recommended to hammer from the shallow interlocking side.
I secure the support columns by applying double-sided tape to the bottom and back surfaces.
It is also possible to cut and use boards up to 3mm thick that you have on hand.