Start of block. The run-in header should be inside the border around this block and there should be no space between the word "header" and the word "Start". The border of the run-in must have no vertical part on the left in the first line and no vertical part on the right in the second line. It must have a vertical part on the right in the first line and a vertical part on the left in the second line. The border of the run-in must not extend outside the border of the block.