MOSAIX is a full-scale, full-size monolithic CMOS pixel sensor prototype developed for the ALICE Inner Tracking System 3 (ITS3), which will replace the three innermost layers of the ALICE tracker during the LHC Long Shutdown 3 (LS3). With over 26 cm in length and 2 cm in width, MOSAIX contains 12 Repeated Sensor Units (RSUs). A single RSU has 12 pixel matrix tiles, each with 444 × 156 pixels and a pixel dimension of 22.8 × 20.8 μm². Power supply and data lines of each RSU are connected by stitching to the power pads on the Left and Right Endcaps and to the readout processing block in the Left Endcap, respectively. MOSAIX is designed to operate with air cooling only and redefines the limits of monolithic CMOS pixel detectors, spanning an entire wafer while pixels maintain over 99% detection efficiency and a fake hit rate below 0.1 pixel⁻¹ s⁻¹. By thinning MOSAIX to 50 μm and supporting it only with ultra-light carbon-foam structures, the ITS3 achieves an average material budget of 0.09% X₀ per layer. Developing an ASIC of this size introduces challenges that go beyond traditional design boundaries. Wafer production failures, no longer confined to individual dies, must be considered by design across the entire stitched wafer. The architecture addresses this by implementing the sensor as a distributed system, where repeated processing units are integrated into a continuous structure and maintained through localized control and fault isolation. With all power and data I/O connections constrained to the short edges, the system must sustain over 30 Gb/s of throughput while remaining below 40 mW/cm² power consumption. This contribution will show how architecture, yield resilience, and power distribution management converge in MOSAIX, illustrating the design principles behind one of the most ambitious wafer-scale detectors built to date.