neural_ca: demonstrate gate composition. A third particle at (0,9) collides with the A&B output particle, so cell (3,5) carries A&B&C, verified over all 8 inputs; chained collisions build larger circuits from the interaction gate. README updated.

neural_ca: the collision is verified as a reversible interaction gate, not just AND. At step 4 three output cells carry A&B (deflected, (3,6)/(6,3)), A&~B ((6,6)), and ~A&B ((3,3)), checked over all four inputs. Analog robustness sweep on the matrix tile: exact under read noise through sigma 0.10 and conductance mismatch through sigma_G 0.10, matching neural_matrix8. README updated.

neural_ca: construct and verify a logic gate in the automaton rather than citing one. A billiard-ball collision between input particles at (2,2) and (7,7) leaves the deflected cell (3,6) occupied at step 4 iff both inputs are present; and_gate() checks the AND truth table over all four inputs. README and docstrings restated as plain technical description of the rule, the verified dynamics, and the constructed gate.

neural_ca: a reversible cellular-automaton computer with no processor. One fixed Margolus block rule (rotate 180, diagonal pairs swap) applied identically to every 2x2 block of a lattice, alternating partition each step. The rule is a self-inverse permutation of the 16 block states, so the whole lattice update is a bijection; verified reversible over random lattices, particle-conserving, with ballistic single-particle motion and deflecting reversible collisions (the billiard-ball model, Turing-universal by Margolus 1984). The rule is Heaviside threshold gates and compiles to a 6-layer ternary matrix tile that is a permutation with a 0.5 margin; that one tile applied to every block is one whole-lattice step, shipped as variants/neural_ca.safetensors. eval_all skips it; README adds the section and updates counts (8 standalone machines, 27-file family round-trip).