The Decap Placement Problem (DPP) is a hardware design optimization challenge where decoupling capacitors must be strategically placed within a power distribution network to minimize impedance and ensure stable power delivery to integrated circuits. 
The problem involves selecting optimal positions for a fixed number of decaps on an n×m grid while avoiding prohibited zones and the probing port location. 
We use a Genetic Algorithm (GA) to solve this problem, evolving populations of candidate placement solutions through selection, crossover, and mutation operations. 
Your task is to evolve a `crossover` function that generates new offspring solutions by combining genetic material from selected parent placements. 
The crossover function should explore the solution space with the goal of maximizing impedance reduction rewards across multiple frequency points and test instances (called "score" or "objective" of solution).