
This could make a great module I thought, so I folded 2 knots from the same size paper and started to look at how they could connect with each other. Several ways became apparent but this one seemed to offer more possibilities, at 90 degrees and with a very firm connection: The point of one covers the other and when pushed follows its line, finishing at the centre of the central square:


With more added, this little beauty emerged:

Very pleased with the result, I then thought about using the units to create a polyhedron: The join is at 90 degrees so a cube should be possible. So 24 freshly folded units later and a lot of fumbling produced this:

Connecting the last face of a cube was quite a struggle. If you're tempted to push your finger through the central square where the 4 loose points meet, it becomes a finger trap!!
Two extra mountain folds are inflicted on the knots where the points bend over to the adjacent 2 sides but they can be soft folds which gives a somewhat puffy appearance to the cube and this way the integrity of the original model isn't really lost.
If you don't mind about this sort of thing you can also push those loose points all the way back into the corners inside the model like this:

Can anyone think of any other model in origami which can be used as a unit in this way without any modification?