4th dimension isn’t that difficult – but it can mess with your mind. if you have the 4th dimension as Time, then you dealing with Time travel – is it just one way or is back and forth – or is there a higher dimension of time that goes “up and down” – allowing you to leap “out of time” and pop into any other time. if you have the 4th dimension as Spacial, then you’re in the land of hypercubes and s…uch. That would allow you to disappear/reappear in the three common dimensions. Of course, you wouldn’t fully disappear – it would just appear so, depending on which way you’re oriented (look up hypercube animations and you’ll see the part in the rotation that it seems to disappear). I love this stuff. I love the idea of higher dimensions but not a fan of the ‘tiny curled up dimensions” in string theory – give me gigantic dimensions that I can men… “