Argon Compact Clockwork Notation · 17 Wallpaper Groups → 68 Forward Groups

Argon Compact Clockwork Notation

Every one of the 68 forward clockwork groups (the 68 polar 3D space groups / cyclic wallpaper colourings) specified by assigning independent time shifts τ(gᵢ) ∈ ℝ/ℤ to a minimal decoupled generating set of each of the 17 wallpaper groups.

1. How Common is the Unconstrained Grid? (The 17-Group Census)

In The Symmetries of Things, a wallpaper group's orbifold presentation lists one generator per orbifold feature, which couples their time shifts via linear congruence relations (such as τ(α) + τ(β) + τ(γ) ≡ 0 (mod 1) in 333, 442, 632, or τ(Q) = τ(R) in *632). When we switch to Argon minimal generators — eliminating the redundant orbifold generator (γ = (αβ)⁻¹, α = (βγ)⁻¹, δ = (αβγ)⁻¹, β = αZ⁻²) and replacing odd-corner mirror pairs by rotations (α = PQ in *632, α = PQ, β = QR in *333, s = PZ in *×) — all coupling equations disappear across all 17 wallpaper groups: the valid clockwork homomorphisms form an unconstrained Cartesian product grid ℤd₁ × … × ℤdₖ of 104 total cells.

Why do those 104 unconstrained grid cells yield 68 distinct forward clockwork groups? Because the size of the unconstrained homomorphism grid |Γabcw| ∈ {1, 2, 4, 6, 8, 9, 16} is an intrinsic invariant of Γ, and two grid cells define the same spacetime group if and only if an outer crystallographic symmetry of Γ (permuting equivalent rotation centres or perpendicular mirrors) maps one tuple to the other:

Regime I · Exact Unconstrained Grid7 groups · 17 cw

100% 1-to-1 bijection (orbit size = 1 for every cell): every point of ℤd₁ × … × ℤdₖ is a distinct forward clockwork group.

Includes p6m (*632) on (α, R) ∈ ℤ₂ × ℤ₂ (2×2 = 4), p6 (632) on (β, γ) ∈ ℤ₃ × ℤ₂ (3×2 = 6), cm (*×) on (P, s) ∈ ℤ₂ × ℤ₁ (2×1 = 2), p3m1 (*333) on (P, α, β) ∈ ℤ₂ × ℤ₁² (2×1×1 = 2), and the 3 drift-pinned groups p1, pm, pg (1 each).

Regime II · Mirror-Inversion 2D Grid2 groups · 10 cw

Exact 2D product grid after τ(α) ~ −τ(α): generated by an off-mirror rotation α and a mirror P.

Because P reflects the rotation centre α into the second rotation centre α' = Pα⁻¹P in the cell with τ(α') = −τ(α), shifting between the two centres folds ℤₙ to ℤₙ/±: p31m (3*3) becomes {0, ±⅓} × {0, ½} (2×2 = 4) and p4g (4*2) becomes {0, ±¼, ½} × {0, ½} (3×2 = 6).

Regime III · Pair-Symmetric 2³ Cube3 groups · 18 cw

Exact 3 × 2 = 6 product grid after swapping 2 identical involutions: Γab ≅ ℤ₂³ has size 8 (a 2-group cannot have size 6), with 3 independent binary generators.

Two of the 3 involutions are geometrically interchangeable (α ↔ β in pmg, P ↔ Q in cmm, P ↔ R in p4m), collapsing their 2×2 = 4 factor to {00, 0½, ½½} of size 3 and leaving an exact 3 × 2 = 6 grid!

Regime IV · Multi-Centre Grid Orbits5 groups · 23 cw

Unconstrained homomorphism grid modded by cell permutations: relations still impose zero coupling between the Argon generators, and cell symmetries merge off-diagonal tuples into centred lattices.

p4 (442): 6 of 4×2 = 8; pgg (22×): 4 of 2×4 = 8; p3 (333): 4 of 3×3 = 9; p2 (2222): 3 of 2³ = 8; pmm (*2222): 6 D₄-necklaces of 2⁴ = 16.

Worked Example · Why 2222 (p2) Has an Unconstrained 2³ = 8 Cube yet 3 Colourings (1 + 6 + 1) 16 raw → 8 valid homomorphisms → 3 distinct groups

Layer 1 · Homomorphism Grid (2⁴ = 16 → 2³ = 8, zero coupling equations)

In Chaim's 4-generator orbifold presentation ⟨α, β, γ, δ | α² = β² = γ² = δ² = αβγδ = 1⟩ for the four half-turn centres at (0,0), (½,0), (0,½), (½,½), the relation αβγδ = 1 forces the linear parity constraint τ(α) + τ(β) + τ(γ) + τ(δ) ≡ 0 (mod 1), ruling out odd numbers of flipping centres (only 8 of the 2⁴ = 16 binary combinations are valid). Eliminating the redundant 4th half-turn δ = (αβγ)⁻¹ leaves the 3 Argon minimal generators (α, β, γ) with presentation ⟨α, β, γ | α² = β² = γ² = (αβγ)² = 1⟩. Because 2(τ(α) + τ(β) + τ(γ)) ≡ 0 (mod 1) holds automatically for every (τ(α), τ(β), τ(γ)) ∈ {0, ½}³, all 2 × 2 × 2 = 8 cube cells are valid homomorphisms with zero coupling equations, and the 4th centre is reconstructed via τ(δ) ≡ τ(α) + τ(β) + τ(γ) (mod 1).

Layer 2 · Relabelling the 4 Unit-Cell Centres (8 cells → 1 + 6 + 1 = 3 colourings)

Why do those 8 valid homomorphisms yield 3 colourings (P2, C2, P2₁) instead of 8? Because the four 2-fold centres (α, β, γ, δ) in a p2 unit cell are geometrically interchangeable: shifting the origin by a half-period or changing the lattice basis permutes the 4 centres by S₄. Once we append the induced 4th shift τ(δ), the 8 tuples partition into 3 orbits according to how many of the 4 centres in the unit cell flip (Hamming weight w ∈ {0, 2, 4}) — all C(4,2) = 6 ways of choosing which 2 of the 4 centres flip produce the same centred group C2:

(τ(α), τ(β), τ(γ)) in 2³ Cube Induced τ(δ) Full 4-Centre Pattern (α, β, γ, δ) Flipping Centres Cube Orbit Polar Space Group / Colouring
(0, 0, 0) 0 (0, 0, 0, 0) 0 of 4 flip (all static) 1/8 P2 (2222, g5)
1 of (α,β,γ) flips: (0,0,½), (0,½,0), (½,0,0)
2 of (α,β,γ) flip: (0,½,½), (½,0,½), (½,½,0)
½ (×3)
0 (×3)
(0,0,½,½), (0,½,0,½), (½,0,0,½)
(0,½,½,0), (½,0,½,0), (½,½,0,0)
2 of 4 flip (all C(4,2) = 6 pairs) 6/8 C2 (c222₁2₁, g7)
(½, ½, ½) ½ (½, ½, ½, ½) 4 of 4 flip (all flip) 1/8 P2₁ (2₁2₁2₁2₁, g6)

2. Master 17-Row Table of All 68 Forward Clockwork Groups

Phase key: g0 static g½ flip g⅓,⅔ third g¼,¾ quarter
Wallpaper Group (17 Rows) · Argon Minimal Generators & Grid Argon Compact Notation Induced Shift Grid Orbit Polar Space Group Clockwork & Chaim Period & Kernel
#1 p1 ◦ Triclinic
I · Exact 1×1 Grid 1 × 1 = 1 cells → 1 group
Argon generators (2): X (translation (1,0), Z1), Y (translation (0,1), Z1)
Relations: ⟨X, Y | XY = YX⟩
Reconstruction: No redundant orbifold generators.

Pure translations on a primitive lattice are gauge-pinned to τ(X) = τ(Y) = 0 by a Galilean frame boost.

τ(X) × τ(Y)
0
0P1g1
X0 Y0
τ(X)=0, τ(Y)=0
— 1/1
{(0, 0)}
P1 #1 o
Chaim: ◦
N = 1
K = p1 (◦)
#2 p2 2222 T-Monoclinic
IV · 2³ Cube Orbits (S₄) 2 × 2 × 2 = 8 cells → 3 groups
Argon generators (3): α (half-turn at (0,0), Z2), β (half-turn at (½,0), Z2), γ (half-turn at (0,½), Z2)
Relations: ⟨α, β, γ | α² = β² = γ² = (αβγ)² = 1⟩
Reconstruction: δ = (αβγ)⁻¹ ⇒ τ(δ) ≡ τ(α) + τ(β) + τ(γ) (mod 1)

Eliminates the 4th half-turn δ = (αβγ)⁻¹ from Chaim's αβγδ = 1 (reducing 2⁴ = 16 raw tuples to an unconstrained 2³ = 8 cube where α, β, γ are independently 0 or ½). Why 3 colourings instead of 8? Because the four 2-centres (α, β, γ, δ) in the unit cell are geometrically interchangeable (S₄): including the induced τ(δ), the 8 cube cells partition into 1 + 6 + 1 = 8 by how many of the 4 centres flip (0, 2, or 4 — see worked walkthrough above).

α0 β0 γ0
τ(α)=0, τ(β)=0, τ(γ)=0
τ(δ) = 0 1/8
(0,0,0) ⇒ δ=0: 0 of 4 centres flip
P2 #3 2222
Chaim: 2222
N = 1
K = p2 (2222)
α½ β½ γ½
τ(α)=½, τ(β)=½, τ(γ)=½
τ(δ) = ½ 1/8
(½,½,½) ⇒ δ=½: all 4 centres flip
P2₁ #4 2₁2₁2₁2₁
Chaim: ²2²2²2²2
N = 2
K = p1 (◦)
α0 β0 γ½
τ(α)=0, τ(β)=0, τ(γ)=½
τ(δ) = ½ 6/8
3 with 1 of (α,β,γ)=½ (δ=½) + 3 with 2 of (α,β,γ)=½ (δ=0) → all C(4,2)=6 pairs of 2/4 flipping centres
C2 #5 c222₁2₁
Chaim: ¹2¹2²2²2
N = 2
K = p2 (2222)
#3 pm ** R-Monoclinic
I · Exact 1×1×1 Grid 1 × 1 × 1 = 1 cells → 1 group
Argon generators (3): P (mirror x = 0, Z1), Q (mirror x = ½, Z1), α (translation (0,1), Z1)
Relations: ⟨P, Q, α | P² = Q² = 1, αP = Pα, αQ = Qα⟩
Reconstruction: Matches the 3 minimal generators of **.

Continuous drift along the mirrors is gauge-pinned (τ(α) = 0); flipping a mirror in ** without perpendicular pinning either rescales the cell or changes the 2D projection to pg/cm, leaving the single polar group Pm.

τ(P), τ(Q) × τ(α)
0
0, 0Pmg10
P0 Q0 α0
τ(P)=0, τ(Q)=0, τ(α)=0
— 1/1
{(0, 0, 0)}
Pm #6 **
Chaim: **
N = 1
K = pm (**)
#4 pg ×× R-Monoclinic
I · Exact 1×1 Grid 1 × 1 = 1 cells → 1 group
Argon generators (2): Y (glide along x = 0, Z1), Z (glide along x = ½, Z1)
Relations: ⟨Y, Z | Y²Z² = 1⟩
Reconstruction: Matches the 2 minimal glide generators of ××.

Along the parallel glides, Y² = T_(0,1) and Z² = T_(0,-1) are pure translations pinned to 0, and a frame shift along the glide axis gauges τ(Y) = τ(Z) = 0.

τ(Y) × τ(Z)
0
0Pcg11
Y0 Z0
τ(Y)=0, τ(Z)=0
— 1/1
{(0, 0)}
Pc #7 ××
Chaim: ××
N = 1
K = pg (××)
#5 cm *× R-Monoclinic
I · Exact 2×1 Grid 2 × 1 = 2 cells → 2 groups
Argon generators (2): P (mirror y = x, Z2), s (primitive slide PZ, Z1)
Relations: ⟨P, s | P² = 1, (Ps)² = sPsP⟩
Reconstruction: Z = Ps ⇒ τ(Z) ≡ τ(P) + τ(s) = τ(P) (mod 1)

Replaces Chaim's coupled (P, Z) (where τ(P) = τ(Z)) with the mirror P and primitive translation s = PZ. Since τ(s) = 0 on the pinned lattice, τ(P) ∈ {0, ½} is a single unconstrained binary flip!

τ(P) × τ(s)
0
0Cmg8
½Ccg9
P0 s0
τ(P)=0, τ(s)=0
τ(Z) = 0 1/2
(0, 0) — mirror static
Cm #8 *×
Chaim: *×
N = 1
K = cm (*×)
P½ s0
τ(P)=½, τ(s)=0
τ(Z) = ½ 1/2
(½, 0) — mirror flips
Cc #9 ~*×½
Chaim: *²×²
N = 2
K = p1 (◦)
#6 pmm *2222 Orthorhombic
IV · 2⁴ Hypercube Orbits (D₄) 2 × 2 × 2 × 2 = 16 cells → 6 groups
Argon generators (4): P (mirror x = 0, Z2), Q (mirror y = 0, Z2), R (mirror x = ½, Z2), S (mirror y = ½, Z2)
Relations: ⟨P, Q, R, S | P² = Q² = R² = S² = (PQ)² = (QR)² = (RS)² = (SP)² = 1⟩
Reconstruction: All 4 mirrors are independent binary flips; centring translations are PR (along x) and QS (along y).

*2222 requires 4 generators (cannot be generated by 3). Because all four corners have even order 2, there are ZERO coupling equations: all 2⁴ = 16 binary combinations (τ(P),τ(Q),τ(R),τ(S)) ∈ {0,½}⁴ are valid, and the 6 groups are the 6 D₄ necklaces of the rectangle's 4 sides!

τ(P), τ(R) [x-mirrors] × τ(Q), τ(S) [y-mirrors]
0, 00, ½½, 0½, ½
0, 0Pmm2g54Amm2g64Amm2g64Pmc2₁g60
0, ½Amm2g64Fmm2g74Fmm2g74Aem2g65
½, 0Amm2g64Fmm2g74Fmm2g74Aem2g65
½, ½Pmc2₁g60Aem2g65Aem2g65Pcc2g55
P0 Q0 R0 S0
τ(P)=0, τ(Q)=0, τ(R)=0, τ(S)=0
0/4 mirrors flip 1/16
(0,0,0,0) — 0 sides flip
Pmm2 #25 *2222
Chaim: *2222
N = 1
K = pmm (*2222)
P½ Q½ R½ S½
τ(P)=½, τ(Q)=½, τ(R)=½, τ(S)=½
4/4 mirrors flip 1/16
(½,½,½,½) — all 4 sides flip
Pcc2 #27 *~2~2~2~2
Chaim: *²2²2²2²2
N = 2
K = p2 (2222)
P0 Q½ R0 S½
τ(P)=0, τ(Q)=½, τ(R)=0, τ(S)=½
2/4 mirrors flip 2/16
(0,½,0,½) ~ (½,0,½,0) — 2 opposite sides flip
Pmc2₁ #26 *2₁~2₁2₁~2₁
Chaim: *¹2²2¹2²2
N = 2
K = pm (**)
P0 Q0 R0 S½
τ(P)=0, τ(Q)=0, τ(R)=0, τ(S)=½
1/4 mirrors flip 4/16
4 tuples with 1 side = ½
Amm2 #38 c*222₁2₁ᵃ
Chaim: *¹2¹2¹2²2
N = 2
K = pmm (*2222)
P0 Q½ R½ S½
τ(P)=0, τ(Q)=½, τ(R)=½, τ(S)=½
3/4 mirrors flip 4/16
4 tuples with 3 sides = ½
Aem2 #39 c*222₁2₁ᵇ
Chaim: *¹2²2²2²2
N = 2
K = pmg (22*)
P0 Q0 R½ S½
τ(P)=0, τ(Q)=0, τ(R)=½, τ(S)=½
2/4 mirrors flip 4/16
4 tuples with 2 adjacent sides = ½
Fmm2 #42 c*22₁22₁
Chaim: *¹2¹2²2²2
N = 2
K = cmm (2*22)
#7 pmg 22* Orthorhombic
III · Factored 3×2 Grid (2³ / S₂) 2 × 2 × 2 = 8 cells → 6 groups
Argon generators (3): α (half-turn at (0,0), Z2), β (half-turn at (0,½), Z2), P (mirror x = ¼, Z2)
Relations: ⟨α, β, P | α² = β² = P² = 1, (αβ)P = P(αβ)⟩
Reconstruction: Centring shift along y is τ(αβ) ≡ τ(α) + τ(β) (mod 1).

22* requires 3 generators. The commutation relation (αβ)P = P(αβ) is trivial in Γᵃᵇ, so (τ(α), τ(β), τ(P)) ∈ {0, ½}³ is an unconstrained 2³ = 8 cube. Swapping the two 2-centre classes α ↔ β merges only (0,½,τ(P)) ~ (½,0,τ(P)), factoring into an exact 3 × 2 = 6 grid!

{τ(α), τ(β)} × τ(P)
0½
0, 0Pma2g56Pnc2g57
0, ½ (×2)Ama2g66Aea2g67
½, ½Pmn2₁g62Pca2₁g61
α0 β0 P0
τ(α)=0, τ(β)=0, τ(P)=0
τ(αβ) = 0 1/8
(0, 0, 0)
Pma2 #28 22*
Chaim: 22*
N = 1
K = pmg (22*)
α0 β0 P½
τ(α)=0, τ(β)=0, τ(P)=½
τ(αβ) = 0 1/8
(0, 0, ½)
Pnc2 #30 22~*
Chaim: ¹2¹2*²
N = 2
K = p2 (2222)
α½ β½ P½
τ(α)=½, τ(β)=½, τ(P)=½
τ(αβ) = 0 1/8
(½, ½, ½)
Pca2₁ #29 2₁2₁~*
Chaim: ²2²2*²
N = 2
K = pg (××)
α½ β½ P0
τ(α)=½, τ(β)=½, τ(P)=0
τ(αβ) = 0 1/8
(½, ½, 0)
Pmn2₁ #31 2₁2₁*
Chaim: ²2²2*¹
N = 2
K = pm (**)
α0 β½ P0
τ(α)=0, τ(β)=½, τ(P)=0
τ(αβ) = ½ 2/8
(0, ½, 0) ~ (½, 0, 0) [α ↔ β]
Ama2 #40 c22₁*ᵃ
Chaim: ¹2²2*¹
N = 2
K = pmg (22*)
α0 β½ P½
τ(α)=0, τ(β)=½, τ(P)=½
τ(αβ) = ½ 2/8
(0, ½, ½) ~ (½, 0, ½) [α ↔ β]
Aea2 #41 c22₁*ᵇ
Chaim: ¹2²2*²
N = 2
K = pgg (22×)
#8 pgg 22× Orthorhombic
IV · 2×4 Grid Orbits 2 × 4 = 8 cells → 4 groups
Argon generators (2): α (half-turn at (0,0), Z2), Z (glide (-x+½, y+½), Z4)
Relations: ⟨α, Z | α² = (αZ⁻²)² = 1⟩
Reconstruction: β = αZ⁻² ⇒ τ(β) ≡ τ(α) − 2τ(Z) (mod 1)

Eliminates the second half-turn β = αZ⁻² from Chaim's α² = β² = αβZ² = 1. In Γᵃᵇ, 2τ(α) ≡ 0 and 4τ(Z) ≡ 2τ(α) ≡ 0, giving an unconstrained Z₂ × Z₄ (2 × 4 = 8) grid with τ(β) ≡ τ(α) − 2τ(Z) (mod 1).

α0 Z0
τ(α)=0, τ(Z)=0
τ(β) = 0 1/8
(0, 0)
Pba2 #32 22×
Chaim: 22×
N = 1
K = pgg (22×)
α0 Z½
τ(α)=0, τ(Z)=½
τ(β) = 0 1/8
(0, ½)
Pnn2 #34 22×½
Chaim: ¹2¹2ײ
N = 2
K = p2 (2222)
α½ Z0
τ(α)=½, τ(Z)=0
τ(β) = ½ 2/8
(½, 0) ~ (½, ½) [x ↔ y axis swap]
Pna2₁ #33 2₁2₁×
Chaim: ²2²2×¹
N = 2
K = pg (××)
α0 Z¼
τ(α)=0, τ(Z)=¼
τ(β) = ½ 4/8
{0, ½} × {¼, ¾} — all 4 quarter-glide cells
Fdd2 #43 c22₁×¼
Chaim: ¹2²2×⁴
N = 4
K = p2 (2222)
#9 cmm 2*22 Orthorhombic
III · Factored 2×3 Grid (2³ / S₂) 2 × 2 × 2 = 8 cells → 6 groups
Argon generators (3): α (off-mirror half-turn, Z2), P (mirror x = 0, Z2), Q (mirror y = 0, Z2)
Relations: ⟨α, P, Q | α² = P² = Q² = (PQ)² = (QαPα⁻¹)² = 1⟩
Reconstruction: Corner 2-centre PQ has τ(PQ) ≡ τ(P) + τ(Q) (mod 1).

2*22 requires 3 generators. Both (PQ)² = 1 and (QαPα⁻¹)² = 1 vanish in Γᵃᵇ, so (τ(α), τ(P), τ(Q)) ∈ {0, ½}³ is an unconstrained 2³ = 8 cube. Swapping the perpendicular mirrors P ↔ Q merges only (τ(α),0,½) ~ (τ(α),½,0), giving an exact 2 × 3 = 6 grid!

τ(α) × {τ(P), τ(Q)}
0, 00, ½ (×2)½, ½
0Cmm2g68Ima2g73Ccc2g69
½Imm2g71Cmc2₁g70Iba2g72
α0 P0 Q0
τ(α)=0, τ(P)=0, τ(Q)=0
τ(PQ) = 0 1/8
(0, 0, 0)
Cmm2 #35 2*22
Chaim: 2*22
N = 1
K = cmm (2*22)
α0 P½ Q½
τ(α)=0, τ(P)=½, τ(Q)=½
τ(PQ) = 0 1/8
(0, ½, ½)
Ccc2 #37 2*~2~2
Chaim: ¹2*²2²2
N = 2
K = p2 (2222)
α½ P0 Q½
τ(α)=½, τ(P)=0, τ(Q)=½
τ(PQ) = ½ 2/8
(½, 0, ½) ~ (½, ½, 0) [P ↔ Q]
Cmc2₁ #36 2₁*2₁~2₁
Chaim: ²2*¹2²2
N = 2
K = cm (*×)
α½ P0 Q0
τ(α)=½, τ(P)=0, τ(Q)=0
τ(PQ) = 0 1/8
(½, 0, 0)
Imm2 #44 c2₁*22ᵃ
Chaim: ²2*¹2¹2
N = 2
K = pmm (*2222)
α½ P½ Q½
τ(α)=½, τ(P)=½, τ(Q)=½
τ(PQ) = 0 1/8
(½, ½, ½)
Iba2 #45 c2₁*22ᵇ
Chaim: ²2*²2²2
N = 2
K = pgg (22×)
α0 P0 Q½
τ(α)=0, τ(P)=0, τ(Q)=½
τ(PQ) = ½ 2/8
(0, 0, ½) ~ (0, ½, 0) [P ↔ Q]
Ima2 #46 c2*2₁2₁
Chaim: ¹2*¹2²2
N = 2
K = pmg (22*)
#10 p4 442 Tetragonal
IV · 4×2 Grid Orbits 4 × 2 = 8 cells → 6 groups
Argon generators (2): α (quarter-turn at (0,0), Z4), γ (half-turn at (½,0), Z2)
Relations: ⟨α, γ | α⁴ = γ² = (αγ)⁴ = 1⟩
Reconstruction: β = (αγ)⁻¹ ⇒ τ(β) ≡ −τ(α) − τ(γ) (mod 1)

Eliminates the second 4-centre β = (αγ)⁻¹ from Chaim's α⁴ = β⁴ = γ² = αβγ = 1. Since 4τ(α) + 4τ(γ) ≡ 0 (mod 1) holds automatically for τ(α) ∈ Z₄, τ(γ) ∈ Z₂, (α, γ) forms an unconstrained 4 × 2 = 8 grid! Swapping the two 4-centres α ↔ β merges only the 2 centred pairs where τ(α) ≠ τ(β).

α0 γ0
τ(α)=0, τ(γ)=0
τ(β) = 0 1/8
(0, 0) → τ(β) = 0
P4 #75 442
Chaim: 442
N = 1
K = p4 (442)
α½ γ0
τ(α)=½, τ(γ)=0
τ(β) = ½ 1/8
(½, 0) → τ(β) = ½
P4₂ #77 4₂4₂2
Chaim: ²4²4¹2
N = 2
K = p2 (2222)
α¾ γ½
τ(α)=¾, τ(γ)=½
τ(β) = ¾ 1/8
(¾, ½) → τ(β) = ¾ (left-handed 4₁)
P4₁ #76 4₁4₁2₁
Chaim: ⁴4⁴4²2
N = 4
K = p1 (◦)
α¼ γ½
τ(α)=¼, τ(γ)=½
τ(β) = ¼ 1/8
(¼, ½) → τ(β) = ¼ (right-handed 4₃)
P4₃ #78 4₃4₃2₁
Chaim: ⁴4⁴4²2
N = 4
K = p1 (◦)
α0 γ½
τ(α)=0, τ(γ)=½
τ(β) = ½ 2/8
(0, ½) ~ (½, ½) [α ↔ β swap: {0, ½}]
I4 #79 c44₂2₁
Chaim: ¹4²4²2
N = 2
K = p4 (442)
α¼ γ0
τ(α)=¼, τ(γ)=0
τ(β) = ¾ 2/8
(¼, 0) ~ (¾, 0) [α ↔ β swap: {¼, ¾}]
I4₁ #80 c4₁4₃2
Chaim: ⁴4⁴4¹2
N = 4
K = p2 (2222)
#11 p4m *442 Tetragonal
III · Factored 3×2 Grid (2³ / S₂) 2 × 2 × 2 = 8 cells → 6 groups
Argon generators (3): P (leg mirror y = 0, Z2), Q (diagonal mirror y = x, Z2), R (leg mirror x = ½, Z2)
Relations: ⟨P, Q, R | P² = Q² = R² = (PQ)⁴ = (QR)⁴ = (RP)² = 1⟩
Reconstruction: 4-turns have τ(PQ) = τ(P)+τ(Q) and τ(QR) = τ(Q)+τ(R).

*442 requires 3 generators. Because all three corner orders (4, 4, 2) are even, there are ZERO coupling constraints: (τ(P), τ(Q), τ(R)) ∈ {0, ½}³ is an unconstrained 2³ = 8 cube. Swapping the two 4-corner leg mirrors P ↔ R merges only (0,τ(Q),½) ~ (½,τ(Q),0), factoring into an exact 3 × 2 = 6 grid!

{τ(P), τ(R)} [legs] × τ(Q) [diagonal]
0½
0, 0P4mmg128P4₂mcg129
0, ½ (×2)I4mmg136I4cmg138
½, ½P4₂cmg130P4ccg131
P0 Q0 R0
τ(P)=0, τ(Q)=0, τ(R)=0
τ(PR) = 0 1/8
(0, 0, 0)
P4mm #99 *442
Chaim: *442
N = 1
K = p4m (*442)
P0 Q½ R0
τ(P)=0, τ(Q)=½, τ(R)=0
τ(PR) = 0 1/8
(0, ½, 0)
P4₂mc #105 *4₂~4₂2
Chaim: *¹4²4¹2
N = 2
K = pmm (*2222)
P½ Q0 R½
τ(P)=½, τ(Q)=0, τ(R)=½
τ(PR) = 0 1/8
(½, 0, ½)
P4₂cm #101 *~4₂4₂~2
Chaim: *²4¹4²2
N = 2
K = cmm (2*22)
P½ Q½ R½
τ(P)=½, τ(Q)=½, τ(R)=½
τ(PR) = 0 1/8
(½, ½, ½)
P4cc #103 *~4~4~2
Chaim: *²4²4²2
N = 2
K = p4 (442)
P0 Q0 R½
τ(P)=0, τ(Q)=0, τ(R)=½
τ(PR) = ½ 2/8
(0, 0, ½) ~ (½, 0, 0) [P ↔ R]
I4mm #107 c*44₂2₁ᵃ
Chaim: *¹4¹4²2
N = 2
K = p4m (*442)
P0 Q½ R½
τ(P)=0, τ(Q)=½, τ(R)=½
τ(PR) = ½ 2/8
(0, ½, ½) ~ (½, ½, 0) [P ↔ R]
I4cm #108 c*44₂2₁ᵇ
Chaim: *¹4²4²2
N = 2
K = p4g (4*2)
#12 p4g 4*2 Tetragonal
II · Factored 3×2 Grid (Z₄/± × Z₂) 4 × 2 = 8 cells → 6 groups
Argon generators (2): α (quarter-turn at 4-centre, Z4), P (nearest mirror, Z2)
Relations: ⟨α, P | α⁴ = P² = (PαPα⁻¹)² = 1⟩
Reconstruction: Mirror-image 4-centre α' = Pα⁻¹P has τ(α') ≡ −τ(α) (mod 1).

(PαPα⁻¹)² = 1 is a commutator squared, imposing ZERO constraint in Γᵃᵇ: (τ(α), τ(P)) ∈ Z₄ × Z₂ is an unconstrained 4 × 2 = 8 grid. Because the mirror P maps the 4-centre α to the second 4-centre α' = Pα⁻¹P with τ(α') = −τ(α), shifting between the two 4-centres identifies τ(α) = ¼ with ¾, yielding an exact 3 × 2 = 6 grid!

α0 P0
τ(α)=0, τ(P)=0
τ(α') = 0 1/8
(0, 0)
P4bm #100 4*2
Chaim: 4*2
N = 1
K = p4g (4*2)
α½ P½
τ(α)=½, τ(P)=½
τ(α') = ½ 1/8
(½, ½)
P4₂bc #106 4₂*~2
Chaim: ²4*²2
N = 2
K = pgg (22×)
α½ P0
τ(α)=½, τ(P)=0
τ(α') = ½ 1/8
(½, 0)
P4₂nm #102 4₂*2
Chaim: ²4*¹2
N = 2
K = cmm (2*22)
α0 P½
τ(α)=0, τ(P)=½
τ(α') = 0 1/8
(0, ½)
P4nc #104 4*~2
Chaim: ¹4*²2
N = 2
K = p4 (442)
α¼ P0
τ(α)=¼, τ(P)=0
τ(α') = ¾ 2/8
(¼, 0) ~ (¾, 0) [α ↔ Pα⁻¹P]
I4₁md #109 c4₃*2
Chaim: ⁴4*¹2
N = 4
K = pmm (*2222)
α¼ P½
τ(α)=¼, τ(P)=½
τ(α') = ¾ 2/8
(¼, ½) ~ (¾, ½) [α ↔ Pα⁻¹P]
I4₁cd #110 c4₁*2
Chaim: ⁴4*²2
N = 4
K = pgg (22×)
#13 p3 333 Trigonal
IV · 3×3 Grid Orbits (S₃) 3 × 3 = 9 cells → 4 groups
Argon generators (2): α (third-turn at (0,0), Z3), β (third-turn at (⅓,⅔), Z3)
Relations: ⟨α, β | α³ = β³ = (αβ)³ = 1⟩
Reconstruction: γ = (αβ)⁻¹ ⇒ τ(γ) ≡ −τ(α) − τ(β) (mod 1)

Eliminates the third 3-centre γ = (αβ)⁻¹ from Chaim's α³ = β³ = γ³ = αβγ = 1 (which started with 3³ = 27 price lists and used the sum rule to reach 9). With 2 minimal generators (α, β), 3τ(α) + 3τ(β) ≡ 0 holds automatically, so you start directly at the unconstrained 3 × 3 = 9 grid! The 3 diagonal cells give P3, P3₁, P3₂, and all 6 off-diagonal cells (τ(α) ≠ τ(β)) give R3.

α0 β0
τ(α)=0, τ(β)=0
τ(γ) = 0 1/9
(0, 0) → τ(γ) = 0
P3 #143 333
Chaim: 333
N = 1
K = p3 (333)
α⅔ β⅔
τ(α)=⅔, τ(β)=⅔
τ(γ) = ⅔ 1/9
(⅔, ⅔) → τ(γ) = ⅔
P3₂ #145 3₂3₂3₂
Chaim: ³3³3³3
N = 3
K = p1 (◦)
α⅓ β⅓
τ(α)=⅓, τ(β)=⅓
τ(γ) = ⅓ 1/9
(⅓, ⅓) → τ(γ) = ⅓
P3₁ #144 3₁3₁3₁
Chaim: ³3³3³3
N = 3
K = p1 (◦)
α⅓ β⅔
τ(α)=⅓, τ(β)=⅔
τ(γ) = 0 6/9
All 6 off-diagonal cells where τ(α) ≠ τ(β)
R3 #146 r33₁3₂
Chaim: ³3³3¹3
N = 3
K = p3 (333)
#14 p3m1 *333 Trigonal
I · Exact 2×1×1 Grid 2 × 1 × 1 = 2 cells → 2 groups
Argon generators (3): P (mirror, Z2), α (3-turn PQ, Z1), β (3-turn QR, Z1)
Relations: ⟨P, α, β | P² = α³ = β³ = (Pα)² = (Pβ)² = (αβ)³ = 1⟩
Reconstruction: Q = Pα, R = Qβ ⇒ τ(Q) = τ(R) = τ(P)

*333 requires 3 generators, and in Chaim's 3-mirror basis (P, Q, R) the odd corners (PQ)³ = (QR)³ = (RP)³ = 1 force τ(P) = τ(Q) = τ(R). Replacing Q, R by the corner rotations α = PQ, β = QR diagonalizes Γᵃᵇ ≅ Z₂: τ(α) = τ(β) = 0 are pinned by dihedral inversion, leaving τ(P) ∈ {0, ½} as a single unconstrained binary flip!

τ(P) × τ(α), τ(β)
0, 0
0P3m1g230
½P3c1g231
P0 α0 β0
τ(P)=0, τ(α)=0, τ(β)=0
τ(Q) = τ(R) = 0 1/2
(0, 0, 0) — mirrors static
P3m1 #156 *333
Chaim: *333
N = 1
K = p3m1 (*333)
P½ α0 β0
τ(P)=½, τ(α)=0, τ(β)=0
τ(Q) = τ(R) = ½ 1/2
(½, 0, 0) — all 3 mirrors flip
P3c1 #158 *~3~3~3
Chaim: *²3²3²3
N = 2
K = p3 (333)
#15 p31m 3*3 Trigonal
II · Factored 2×2 Grid (Z₃/± × Z₂) 3 × 2 = 6 cells → 4 groups
Argon generators (2): α (off-mirror third-turn, Z3), P (nearest mirror, Z2)
Relations: ⟨α, P | α³ = P² = (PαPα⁻¹)³ = 1⟩
Reconstruction: Mirror-image 3-centre α' = Pα⁻¹P has τ(α') ≡ −τ(α) (mod 1).

(PαPα⁻¹)³ = 1 is a commutator cubed, imposing ZERO constraint in Γᵃᵇ: (τ(α), τ(P)) ∈ Z₃ × Z₂ is an unconstrained 3 × 2 = 6 grid. Because the mirror P reflects the off-mirror 3-centre α to the second 3-centre α' = Pα⁻¹P with τ(α') = −τ(α), shifting between the two 3-centres identifies τ(α) = ⅓ with ⅔, yielding an exact 2 × 2 = 4 grid!

τ(α) mod ± × τ(P)
0½
0P31mg232P31cg233
±⅓ (×2)R3mg234R3cg235
α0 P0
τ(α)=0, τ(P)=0
τ(α') = 0 1/6
(0, 0)
P31m #157 3*3
Chaim: 3*3
N = 1
K = p31m (3*3)
α0 P½
τ(α)=0, τ(P)=½
τ(α') = 0 1/6
(0, ½)
P31c #159 3*~3
Chaim: ¹3*²3
N = 2
K = p3 (333)
α⅔ P0
τ(α)=⅔, τ(P)=0
τ(α') = ⅓ 2/6
(⅔, 0) ~ (⅓, 0) [α ↔ Pα⁻¹P]
R3m #160 r3₂*3
Chaim: ³3*¹3
N = 3
K = p3m1 (*333)
α⅔ P½
τ(α)=⅔, τ(P)=½
τ(α') = ⅓ 2/6
(⅔, ½) ~ (⅓, ½) [α ↔ Pα⁻¹P]
R3c #161 r3₂*~3
Chaim: ³3*²3
N = 6
K = p3 (333)
#16 p6 632 Hexagonal
I · Exact 3×2 Grid 3 × 2 = 6 cells → 6 groups
Argon generators (2): β (third-turn at (⅓,⅔), Z3), γ (half-turn at (½,½), Z2)
Relations: ⟨β, γ | β³ = γ² = (βγ)⁶ = 1⟩
Reconstruction: α = (βγ)⁻¹ ⇒ τ(α) ≡ −τ(β) − τ(γ) (mod 1)

Eliminates the sixth-turn α = (βγ)⁻¹ from Chaim's α⁶ = β³ = γ² = αβγ = 1. Since 6τ(β) + 6τ(γ) = 2(3τ(β)) + 3(2τ(γ)) ≡ 0 (mod 1) holds automatically for every (τ(β), τ(γ)) ∈ Z₃ × Z₂, the two generators form an EXACT unconstrained 3 × 2 = 6 grid in 1-to-1 bijection with the 6 polar P6_k groups!

τ(β) [3-turn] × τ(γ) [2-turn]
0½
0P6g243P6₃g246
⅔P6₂g244P6₅g247
⅓P6₄g245P6₁g248
β0 γ0
τ(β)=0, τ(γ)=0
τ(α) = 0 1/6
(0, 0) → τ(α) = 0
P6 #168 632
Chaim: 632
N = 1
K = p6 (632)
β⅔ γ0
τ(β)=⅔, τ(γ)=0
τ(α) = ⅓ 1/6
(⅔, 0) → τ(α) = ⅓
P6₂ #171 6₂3₂2
Chaim: ³6³3¹2
N = 3
K = p2 (2222)
β⅓ γ0
τ(β)=⅓, τ(γ)=0
τ(α) = ⅔ 1/6
(⅓, 0) → τ(α) = ⅔
P6₄ #172 6₄3₁2
Chaim: ³6³3¹2
N = 3
K = p2 (2222)
β0 γ½
τ(β)=0, τ(γ)=½
τ(α) = ½ 1/6
(0, ½) → τ(α) = ½
P6₃ #173 6₃32₁
Chaim: ²6¹3²2
N = 2
K = p3 (333)
β⅔ γ½
τ(β)=⅔, τ(γ)=½
τ(α) = ⅚ 1/6
(⅔, ½) → τ(α) = ⅚
P6₅ #170 6₅3₂2₁
Chaim: ⁶6³3²2
N = 6
K = p1 (◦)
β⅓ γ½
τ(β)=⅓, τ(γ)=½
τ(α) = ⅙ 1/6
(⅓, ½) → τ(α) = ⅙
P6₁ #169 6₁3₁2₁
Chaim: ⁶6³3²2
N = 6
K = p1 (◦)
#17 p6m *632 Hexagonal
I · Exact 2×2 Grid 2 × 2 = 4 cells → 4 groups
Argon generators (2): α (sixth-turn PQ at (0,0), Z2), R (mirror opposite 6-centre, Z2)
Relations: ⟨α, R | α⁶ = R² = (αRα⁻¹R)² = (RαRα²)³ = 1⟩
Reconstruction: P = αRα⁻¹Rα, Q = α⁻¹P ⇒ τ(P) ≡ τ(α) + τ(R), τ(Q) = τ(R)

Replaces Chaim's 3 coupled mirrors (P, Q, R) (where (QR)³ = 1 forces τ(Q) = τ(R)) with the sixth-turn α = PQ and mirror R. In Γᵃᵇ ≅ Z₂ × Z₂, both α and R have order 2: each generator is independently non-flipping (0) or flipping (½), forming an EXACT 2 × 2 = 4 unconstrained binary grid!

τ(α) [6-turn] × τ(R) [mirror]
0½
0P6mmg268P6ccg270
½P6₃mcg271P6₃cmg269
α0 R0
τ(α)=0, τ(R)=0
τ(P)=0, τ(Q)=0 1/4
(0, 0) — neither flips
P6mm #183 *632
Chaim: *632
N = 1
K = p6m (*632)
α½ R½
τ(α)=½, τ(R)=½
τ(P)=0, τ(Q)=½ 1/4
(½, ½) — both α and R flip
P6₃cm #185 *6₃~3~2₁
Chaim: *¹6²3²2
N = 2
K = p31m (3*3)
α0 R½
τ(α)=0, τ(R)=½
τ(P)=½, τ(Q)=½ 1/4
(0, ½) — only R flips
P6cc #184 *~6~3~2
Chaim: *²6²3²2
N = 2
K = p6 (632)
α½ R0
τ(α)=½, τ(R)=0
τ(P)=½, τ(Q)=0 1/4
(½, 0) — only α flips
P6₃mc #186 *~6₃32₁
Chaim: *²6¹3¹2
N = 2
K = p3m1 (*333)