A geodesic sphere is just two domes put together, right? Well, yes and no. If you take two even-frequency geodesic domes (2V, 4V, 6V) and connect them on their base rows, you’ll get a sphere with two rings around the center hemisphere. If you try that with odd-frequency domes (3V, 5V), you’ll get either a squashed or elongated sphere. To get a true PVC sphere, you need to use the sphere calculator so that all the lines match up ‘geodesically’.