Each transform is T_k(x)=A_k x + b_k in ℝ². The orbit P_N(θ) is the set of points obtained
by applying length-N words (commutative ↔ multiset) starting from 0. Loss is symmetric
Chamfer (squared NN distance). Gradients flow through TensorFlow.js autodiff. Frozen
transforms are held constant — their gradients are masked to zero before the optimizer
step.