To make a river stone mat first you have to gather or purchase river stones. After that take a plastic mat and arrange all the stones on it. Then stick all the stones one by one to the plastic mat by using silicone sealer. Let the sealer dry completely.
Port - Most input/output devices are outside the computer case. These devices communicate with components inside the computer case through a wireless connection or through pcables attatched to the case at a connection called a port. (Chad G.