Grave goods of Late Neolithic cultures include stone tools, shell beads and bracelets, and accomplished incised and cord-marked ceramics. Evidence of rice cultivation suggests that sedentary living is becoming more prevalent. By the middle of the period, bronze technology develops from locally mined ores, and cast implements and adornments made using both the lost-wax method and bivalve molds have been discovered in Thailand. Numerous rivers and waterways facilitate trade and exchange of goods among the cultures of mainland and island Southeast Asia.