Designing quantum circuits using only measurable quantities

Instead of specifying quantum algorithms as sequences of abstract gates, this model defines computations through constraints on directly measurable Pauli observables, paired with local tomography at each step. The approach is provably universal for quantum computation with only polynomial overhead — a depth-D circuit on N qubits needs at most O(D²N log N) work. The payoff is a programming interface grounded entirely in observable physics, bridging everything from quantum simulation to game procedural generation.