['This', 'is', 'because', 'the', 'rough', 'wall', 'treatment', 'in', 'the', 'soft', 'sphere', 'implementation', 'adds', 'extra', 'virtual', 'walls', 'during', 'the', 'collision', 'of', 'a', 'particle', 'with', 'a', 'wall', ',', 'which', 'is', 'a', 'more', 'realistic', 'representation', 'of', 'a', 'rough', 'wall', 'compared', 'to', 'the', 'hard', 'sphere', 'rough', 'wall', 'treatment', 'where', 'one', 'random', 'wall', 'is', 'considered', '.']