Extend the digit construction to every modulus

The direct extension already fails modulo 4: (3, 0, 1) is a nontrivial progression.

A counterexample modulo 4

The extension to every modulus is false as stated. In ℤ/4ℤ, (3, 0, 1) is a progression with distinct terms.

Why it breaks

The common difference is 1, so 3 + 1 = 0 and 0 + 1 = 1 modulo 4.

Scope

This refutes the direct all-moduli claim. It does not rule out a modified construction for selected moduli.