Plumbing joints are essential components of a plumbing system, used to connect pipes and fixtures. ELLS, also known as ELLS or ELLS, are four-letter joints that form a 90-degree angle. ELBOWS, on the other hand, are six-letter joints that form a 45-degree angle. Finally, TTTT is a four-letter joint that is used to join two pipes together in a straight line. Together, these three types of plumbing joints are essential for creating a functional plumbing system.