Create a painting inspired by Xu Beihong's horse series, depicting the majestic scene of five horses running on the grassland. These horses are depicted vividly, with flowing manes, each having a unique expression and posture. The background is a vast grassland, with swaying grasses creating a beautiful dynamic image with the horses' running. In the distance, the mountains rise and fall, adding a sense of tranquility and solemnity to the entire painting.