Watch the Major Scale online guitar lesson by Brad Carlton from Melodic Patterns

Major Scale Example 20 is given as a model in which you can develop the other three variations. You're simply ascending, going up a third, up a second, up another second. You're still getting all three chord tones of the triad but you have your connecter in the form of a fourth, be it a natural fourth or a sharp fourth, depending upon which scale degree you're building a chord on.