Saying, for example, “that all things are just constructs created by the mind out of Suchness” is not the same as saying “there is only Suchness; fundamentally things do not exist.” The first statement carries with it a tacit division between mind and Suchness. Mind, we could envision, is making things out of raw Suchness. The second statement carries no such division, tacit or otherwise. Things, or all things (sarvadharmâ), are just configurations of Suchness, Suchness being synonymous with the One Mind.
The first statement expresses a mechanical viewpoint (a separation between mind and Suchness) whereas the second statement expresses an organic totality. In this totality, the absolute can be, seemingly, both itself and other; having no awareness of how the two are connected; this connection being concealed, as it were, by dark unknowability (avidya). Or it can also realize otherness, and the subject of otherness, to be mere configurations of itself. In so doing it has converged with itself amounting to perfect and full self-realization which somewhat paradoxically allows for the play of illusion.
A deeper grammar appears, more or less, in most all of the discourses of the Buddha, especially, in Sutras like the Lankavatara Sutra. This is in contrast with conventional grammar which works on a horizontal surface of little or no depth; which we could even say is anti-illuminative.
The difficulty of reading and understanding a grammar of depth is that our conventional education has not prepared us to read such a subtle grammar, especially, Zen Buddhist koans. There is nothing in the West that even comes close to the subtle, unconventional grammar of koans and Sutras like the Lankavatara Sutra.