Okay, here is an analogy and description of the macro-element Ne/Si:
*note: When I use the word "see" or "perceive" I mean the way we filter information which is carried into our minds be our senses. We sense the external world and these senses are filtered based on the 8 information elements. The filtered information causes our thought processes to function in certain ways and that generates conceptions and hence actions/behaviors. This is a crux of socionics.
Take a sheet and lay it across a flat surface like a table or the floor. Observe how its flatness creates a feeling of emptyness and singularity. there are no boundaries between one section of the sheet and another.
Now gather some random objects such as a ball, a cup, a toy, a phonebook, or your cat (sedate him). Place one of them underneath the sheet, smooth out the ruffles, and press down around the object's edges.
As you can see, the object's form has individuated part of the sheet. The sheet is no longer flat and without boundaries because it has a form to shape and separate it.
Now trade that object for another. as you observe the contrats in the new form, notice how you see the sheet directly, not the objects themselves. Also, see how even when you press down around the objects and tuck the sheet under them, you still cannot cut off a part of the sheet over the object from the surrounding sheet. Although we know there are forms under the sheet, we can only perceive them indirectly.
This is what Ne/Si is like (or at least a close analogy). The perception is of a directly tangible context (the sheet), where objects are separated from eachother by indirect abstractions. We cannot "see" the forms directly. the objects are not seen as tangibly discrete and separable. That would involve taking out scissors and cutting the sheet. Instead, although we can divide out the objects by perceiving their internal forms, physically or demonstrably, they are blurred around the edges.
Without its Ne counterpart, Si could not exist in any interpretable form. It would be similar to the sheet without stuff under it. Empty, void, formless, and flat. However right before all Ne was extracted, we might see a chaotic, rippling maelstrom composed of matter and energy.
Without its Si counterpart, Ne also cannot exist. Imagine, if you had suddenly snatched the sheet off the objects and they then disappeared. The "home" or tangible manifestation of these abstract forms has been removed so they cannot exist. Now the Ne collapses back in on itself into a singularity and then into void. Without the Si to reach out, grab, expand, and hence diversify into, the Ne must self-apply, reducing Ne to zero.
When working in unison, these elements are able to exploit and fuel eachother. Si gives Ne a context to not only manifest tangibly, but also to explore, diversify, and generate more Ne forms. Ne gives Si diversity and objectivity. Ne, being an object element, coalesces lumps of the Si flow into a luminescent node of Ne. these nodes are recognizable objects, separable from on another by virtue of the Ne installation of conceptual associations.
Ne/Si can play off eachother from both sides of the coin. We can manipulate the Si flow, melding and transforming it into such a way that bulbs of Ne begin to glow and brighten inside of it. We can also select, insert, and cluster Ne forms into fields of Si, thus causing the subjective nature of Si to mutate into a perceptably new and alternate enviroment. One could imagine the projects of an ISTp craftsperson for the former and the poking/probing acts of an Ne ENTp infantile for the latter.
Representations of Ne>Si:
Representations of Si>Ne: