Figure 15 shows the lengths required to take advantage of the various resonance frequencies at a range of RPMs, up to a maximum length of 40cm. From the upper graph in Figure 15, it can be seen that many of the first-order to third-order harmonics are not usable due to the extremely long lengths required of the runners. A compressed view of the graph (lower graph of Figure 15) shows the required runner lengths, in colored bands, for the various RPMs and their respective orders of harmonics.