Most geodesic domes you see are variations of 'icosahedrons'. All the sonostar domes are derived from icsosahedrons and they all have 6 pentagons built into a design of primarily hexagons that help contribute to the geometric ‘roundness’. If you were given the problem of making a sphere out of nothing but triangles, you would find that the smaller the triangles, the more spherical your model would look. Given the same sized sphere, the smaller the triangles, the more of them there would be. That’s the basic idea around frequency. An easy way to determine the frequency of a dome is to count the poles/struts that connect the centers of the pentagons. So if you start at the top of a geodesic dome and go down toward the next pentagon, you can count the poles from center to center and that will tell you what the frequency is. As the frequency number goes higher, the complexity and number of connectors and struts in the dome also increases. So in a frequency 3 dome, there are three poles between the centers of the pentagons. In a frequency 6 dome, there are six.f