Octave frequencies are always spaced by power of 2, the only intervals which are consistently given a natural tuning. Doubling a frequency, for instance, produces a sound which is an octave higher than the original frequency, as in the combination given here. Octaves blend together better than any other possible musical interval. Although the patterns vary with different octave combination, the patterns always have the same period as the lowest frequency note.
Click to hear this sound as played on a piano: C & C