EulerAngles is an interactive tool for learning about Euler angles and other 3D orientations, such as rotation matrix, equivalent axis, and quaternion. The Euler convention can be easily changed by touching the top bar. The three angles can be modified simply by editing their values or by dragging. Simultaneously, a 3D animation of the three frames is shown while the angles are being modified. The rotation matrix, the equivalent axis, or the quaternion can be shown one at a time, along with the Euler angle frames. The viewpoint can also be modified through simple gestures.