2606.02807 Painting and Steering on a Frozen-Embedding Substrate: a differentiable whole-frame renderer and gradient-based human-in-the-loop steering in Sutra
Sutra is a purely functional language whose values are geometric objects in a vector substrate and whose operations are tensor operations on that substrate; the substrate's axes can be the meaningful directions of a pretrained embedding (used here for glyph fonts), or, where a task needs no semantic codebook, a small codebook-free arithmetic slice of the same machinery (used here for the pixel fields). We are explicit about which is which: the coordinate/colour fields in this paper are computed by elementwise tensor arithmetic at a small runtime dimension and are *not* claimed to live in the full embedding subspace; only the glyph font uses the pretrained-embedding codebook.