Complex sentence: The Inner city city walls had a perimeter of 24 kilometres, it had the rough shape of a square with the eastern and western walls slightly longer due to the northern and southern walls being moved from their Yuan Khanbaliq's original positions.
Split into simpler sentences: The Inner city city walls had a perimeter of 24 kilometres. It was roughly square, with the east and west walls slightly longer due to the north and south walls being moved from Yuan Khanbaliq's original positions.