Container can be stacked on top of each other. The top features a recess for a 6 x 2mm magnet https://www.amazon.de/dp/B09W8P2796?ref=ppx_yo2ov_dt_b_fed_asin_title and two notches for stacking. The bottom features two holes for stacking on wagons and for stacking the container onto each other.
The author marked this model as their own original creation.