Mysterious white triangle lines my brick chimney. After winter I found there are white triangle lines on both side walls around my brick chimney. After raining for 1-2 hours, the brick wall on both side of the chimney will have a deep color triangle area larger and lower than white triangle lines. But, I have touched the deep color area and did not fell water on the brick after rainning lightly several hours. When it does not rain, the deep color triangle area is fading out and can only see it 50 meter away. Till now, we have rain every week. Please help me to find possible reasons? Thank you.