(quoted from Sphereland: A Fantasy About Curved Spaces and an Expanding Universe)
Being a threedimensional creature, he could easily see our expansion. He could see, for example, that the distances between all points on the sphere surface grow and he could also see the psots on the sphere surface move away from each other, whereby the distances between the most widely scattered spots naturally increased more rapidly than those between the closer spots. We were satisfied, but I still had one burning question I dared not ask. My son did dare, however  much to my shocked surprise. he asked whether a similar phenomenon had not een observed in the threedimensional world. Fortunately, the Sphere did not get angry, but said calmly that this was indeed the case. The threedimensional universe contains worlds which are called nebulae, since their vast dinstances cause them to look like tiny, hazy dots. It was observed that theswe little dots were moving away from each other, and there too, just as in our Sphereland, the rate at which they widraw from any other dot increases with distance.
So it is not only possible for a curved, onedimensional world, Circleland, to exist and to expand steadily, but it holds true for a twodimensional world, namely our swelling Sphereland, and even for one of three dimensions, a curved Spaceland which is also expanding steadily. It was clever of the Sphere to understand this, even though he was unable to see it, just as we could not observe our expanding spherical surface.
