This is Grating Tessellation, a new origami design of mine. Vertical walls of the grating divide the whole plane into small cells which give this tessellation some practical uses such as storing small items (nails, screws, etc.) or making ice cubes.
Each molecule uses 3×3 grid units. Collapsing seems hard at first but not more so once you learn the right trick.
Please comment and let me know if you have seen this design before. I think the end result is pretty elegant, but the crease pattern is so simple I think others may have come up with it before.
Update: Nick Robinson pointed me to a very similar model and he says he has seen similar designs in other places, too. This sort of model is known as “box divider technique”. Compared to the video, my model uses a more symmetrical layout of the flaps inside the wall intersection: four small flaps, each one going inside one of the walls, whereas the model shown in the video has just one big flap hidden inside a single wall, but apart from that, they are the same. I also found a beautiful model of a box of chocolates which seems to use the same or very similar technique.