Throughout this course, we've said that VR interaction should be just like real world interaction. But that isn't always possible. Sometimes you want to do things which we just can't do in the real world, or where the real world action is just too complex. We might want to change the color of our furniture but we might not want to actually paint at all. At times, a magical interface might work. But there are somethings that won't feel real even with superpowers. This is where we need more abstract interfaces. We have two options. We can try to keep the interaction body based and use gestures to interact, or we can fall back on using a more traditional graphical user interface, GUI. Gestures are hands and arm movements that trigger events. For example, I might swipe my arm to move through a number of different items in a list just like on the phone. Gestures can feel good because you're moving, and they can be fun. If they can be made seem natural, they might enhance presence. But they can also be tiring and hard to learn and remember if there isn't a very natural gesture like swiping. Graphical user interfaces are what we are used to from computers and phones. They are 2D surfaces with buttons, sliders and other interactive widgets. If you use them in VR, you're importing a touchscreen interface into the virtual world. This might seem like the least natural, least real world type of interaction. But when you think about it, in the 21st century, the real world is absolutely full of 2D graphical interfaces, whether they're on the phones in our pockets, the touchscreens in shopping malls or on the computers that are everywhere. So, having a screen suddenly appear in front of us might not feel that natural at all.