STEM education integrates concepts that are usually taught as separate subjects in different classes and emphasizes the application of knowledge to real-life situations. A lesson or unit in a STEM class is typically based around finding a solution to a real-world problem and tends to emphasize project-based learning. A variation of STEM is STEAM, which includes an 'A' for art and design. Artistic design is becoming an important part of STEM education since creativity is an essential part of innovation. Many STEM lessons involve building models and simulating situations. A good STEM lesson ensures that students understand the connection to the real world.