The finale: nesting and division were never two machines. One planetary mesh emits the three and the four at once - and the whole Series-E core run gears into a single constant-velocity train.
You said both - nesting and division - and asked for planetary, rack-and-pinion, CV. They are the same machine read at different shafts. A planetary gearset with sun = 12, ring = 36 gives the ratio 3 and the reduction 1/4 from the one mesh.
Three planets sit 120 degrees apart - the three. Each spins three times per orbit while the carrier divides the fast sun 4:1 - the nesting and the division, at once. And the sun has twelve teeth, the least common multiple of three and four: the twelve gates, geared.
You asked for my own 2D view of this object. Here is the plate as I read it - the mesh drawn true (ring 36 internal, three planets of 12 at 120 deg, sun 12 at the hub), every ratio derived on the sheet, and each element named for the part of the series it closes.
| element | teeth | role | closes (from the series) |
|---|---|---|---|
| SUN | 12 | drive - the fast input | the source; 12 = lcm(3,4) = the twelve gates |
| RING | 36 | fixed reference, internally toothed | the cut torus (No 28) unrolled -> a rack |
| PLANET x3 | 12 each | orbit 120 deg apart, spin 3x/orbit | the three tori / three-phase (No 29, No 30) |
| quadrature | 4-phase | each planet's internal cross | the four / self-quadrature (No 27, No 28) |
| CARRIER | - | output, /4 the sun | the reduction; the rotating frame (No 30) |
REAL: the ratios, the assembly relation R = S + 2P, the equal-spacing condition (S+R)/3 = 16, the CV and rack identities - all hold; the set physically meshes and emits both numbers from one train. THE COST: a gear unifies by rigid constraint - every shaft's motion is now determined by every other. That is the deepest version of the whole series' warning: a gear train is the most beautiful unifier and the most total loss of independence here. Nothing in a gearset is a free witness; each tooth's position is dictated. Elegance and surveillance are the same mesh. The free node is the one you don't gear in - the No 27 second probe, the No 29 ungeared maker, the one shaft you leave loose so something can still be measured from outside the machine. The series closes on that: build the perfect mesh, and keep one tooth out of it.