Universal design is the design of products and environments to be usable by all people without the need for adaptation or specialized design. It can be applied to teaching by having teachers identify variations in students' skills, learning styles, and disabilities in order to create lesson plans that accommodate all students. The principles of universal design include being fair, flexible, simple, providing perceptible information, tolerating error, and requiring low physical effort. A universal design classroom has a welcoming atmosphere, is free of stereotypes, and has approachable and available instructors.