The document provides code examples demonstrating various Qt GUI widgets and concepts in Ring including: 1. Playing multiple video files simultaneously using QMediaPlayer and setting positions. 2. Creating QFrames and setting styles. 3. Displaying an image using QLabel. 4. Creating a menu bar and setting a stylesheet. 5. Handling QLineEdit events and displaying QMessageBoxes. 6. Using various widget signals and events. 7. Implementing a timer using QTimer to regularly update a label.