Given the current phase of a two-way junction, drive the north-south and east-west lights. Each light output is {red, yellow, green}. Phase 0: NS green, EW red. Phase 1: NS yellow, EW red. Phase 2: NS red, EW green. Phase 3: NS red, EW yellow. (The sequencing counter is a later, sequential exercise; this is the decode only.) Input: phase, 2 bits. Outputs: ns and ew, 3 bits each as {red, yellow, green}. The testbench applies all four phases.