Woven Slit Module is an origami unit which can be used to build different kinds of modular assemblies, from simple cubes to more complex objects. They can weave with other units to form interesting patterns. In some models, these units can slide along one another to produce action origami — assemblies which can be transformed into different shapes without taking the units apart. WSM can be made from rectangular paper of different proportions with broad units being useful for models with densely packed and ornamented walls and thin skinny units being useful for lattice-like models. A paper aspect ratio off 2:1 is a good starting point for many models.
Diagrams in print media
A full step-by-step diagram was published in 13th Bulletin of Polish Origami Society (2015), on page 84.
Instructions are currently only available as a Crease Pattern (CP), but it is very simple, so you should be able to re-create the unit from it even if you have little or no experience with CPs. The CP is for 2:1 paper ratio but any ratio above 3:2 can be used.
Units are connected by inserting the two half-square flaps into the slits in other units. Some assemblies require the units to be additionally bent around each other. Units can be placed so that the slit it either on the inside or on the outside of the model.
Below you can find an example of connecting units for the Cube (2:1 paper, slits outside) model.