Watch the Major Scale online guitar lesson by Brad Carlton from Melodic Patterns
Major Scale Example 18 is oriented around the triads. You have all three notes of each diatonic triad with a connector between the fifth and the third. Your first motif would be the notes C, G, F, E. Therefore it outlines the triad because you have the root, the fifth, the fourth as a passing tone, and then the third. Then you continue this and in doing so you're outlining each of the seven diatonic triads in the key of C.