Ideas in this flowchart

• Portal Mechanics
• Portal Functionality
• Magical Device
• Instant Transport
• Portal Passing Through Itself
• Two-Dimensional Space
• Portal as a Line
• Back-to-Back Portals
• Star Orientation
• Recursive Passage
• Visibility of Portal
• Infinite Thinness
• Flexibility of Portal
• Three-Dimensional Space
• Rotation and Adjustment