A-Shape Triads (Layer 3)
Fretboard Triad Vision with the A, C, and E-Shapes
The A-shape contains the third and final set of triad inversions which, along with what you've studied in the E-shape and C-shape, gives all the possible ways to play close voicing major triads across the entire fretboard.
On string set 1, there is the Root position major triad:
Lowering the 5 gives a second inversion triad on string set 2:
Lowering the 3 (using the C-shape octave) gives a first inversion triad on string set 3:
Lowering the R gives a root position triad on string set 4, which is linking the A-shape to the next shape higher up the fretboard:
My YouTube lesson below goes into more detail about how the triad forms are derived from the different Blueprint Shapes: