My *1st* suggestion was going to be DXM, since it gives you the tools to "put together" your building blocks. DXM expands one's comprehension of 3D/2D space (and other complex ideas), allowing one to fully visualize coherent structures. But (and it's a big-ass but), it doesn't provide the impetus, the wild card to come up with truly new things.
For that impetus, let me suggest cannabis. It roils your emotions, puts instability into your system, disrupts your lattice to the point of thinking about things you might have never arrived at with other drugs (drugs including your day-to-day endogenous makeup). It may take an heroic oral dose.
Similar to cannabis, but with some DXM aspects. Shrooms let you experience completely alien things (like DXM), allow you to partition your internal storage (also like DXM), but seem to also bring you.... something unexpected. It does all this while leaving you more clear-headed than cannabis. You might need to take A LOT.
I have a literature-oriented friend, and he liked DXM (Coricidin, to be exact) above all else. He said it allowed him to "stack his blocks," but he never attained visuals like I did. I can only imagine that he might have been talking about something related to what I experienced, but in a non-visual sense.
So maybe you need DXM, a bunch of shrooms, a *tiny* touch of alcohol, cannabis and perhaps some thujone.
-Mec