Cerberus Cube, a model of my own invention. Ignore the other model leaning on it on the left side.
Many of the origami models I post are simply things I found in books. I like the idea of making my own models, but it's quite difficult. One of the easier ways to go is to start with an known module, and join these modules in an unusual way to create a new model. (I know they sounds similar, but I use "module" or "unit" to refer to the individual pieces, and the "model" to refer to the completed whole.)
So I started with one of the sturdiest modules in modular origami: the Sonobe unit. The Sonobe cube is so classic that it was the very first modular origami I made:
The Sonobe cube. Instructions are available on the internet.
The sonobe unit is a simple square with two pockets and two tabs. If you take six of these squares, you can make the Sonobe cube. But there's no reason to restrict the squares to a symmetric configuration. You can also attach the squares to make 3D tetris pieces, for example. What's more, there's no reason that the squares must be flat. You can fold the square in half to get two 45-45-90 triangles. You can combine these triangles to get unlimited number of shapes, such as the Sonobe icosahedron.
In the model shown at the top, I used this method to make three conjoined Sonobe cubes. Why that shape? It's nothing special or planned, I just wanted to combine Sonobe units in some creative way, and see what would come out. I think of it as the "cerberus cube" because it has three heads.
Perhaps one of these days I'll make a ton of Sonobe units and combine them into something more fantastical.