We present a stellarator coil design framework based on currents constrained to simple modular surfaces, particularly cylindrical segments with precisely defined current paths. The method is embedded in a prototype-driven workflow: the optimization framework is used to produce coil patterns that are realized using high-precision laser-engraving techniques. Small-scale prototypes, including a half-period stellarator coil set, show that optimized surface currents on cylindrical modules can reproduce nested magnetic surfaces with high fidelity. This approach demonstrates that geometric simplification can support both practical coil realization and accurate magnetic confinement, opening new directions for stellarator design and validation.