Complex sentence: The project was started under the tlaoani Chimalpopoca and modified by Moctezuma I. It consisted of a twin-pipe construction made of compacted earth and wood; when one pipe needed maintenance, the water flowed through the other.
Split into simpler sentences: The project was started under the tlaoani Chimalpopoca and modified by Moctezuma I. It consisted of a twin-pipe construction made of compacted earth and wood. When one pipe needed maintenance, the water flowed through the other.