 Settlers were hunter-gatherer desert people with agricultural knowledge; established important irrigation systems for maize cultivation; developed the ability to design and use solar calendars engraved in stone, which indicated the beginning of the seasons of the year.These three cultures established a large communications network and roads that allowed them to develop a far-reaching commercial, cultural and social trade agreements among them.Trade products were baskets and woven objects, ceramics, corn, ritual ornaments, turquoise, seashells, salt, and even knowhow and production technical.