You've spent most of your playing life counting to four. This one is counted in six, in two groups of three. Stop hearing six fast clicks, start feeling two slow pulses, and it rocks: up for three, back for three. That motion is where the title comes from.
All three parts are the same four repeating bars — an original by Steve Anthes in G major, 6/8, straight eighths, standard tuning. The progression is G, Dsus4/F♯, Em7, Cadd9, then back through Dsus4/F♯ to G, with the bass stepping down G – F♯ – E before it leaps up to C and turns for home. Bars 1–4 repeat; one held chord ends it. Tempo is ♩ = 80 — that's the plain quarter note, not the dotted one. The progression never changes; what changes is the job your hands are doing.
Rhythm strums it as four open chords with the top two strings held down through every change — ring finger and pinky planted, never lifting, while the shapes move underneath them. Triads rolls the same progression two notes at a time out of chord shapes, climbing in one bar and falling in the next, so each bar builds its chord out of overlapping pairs instead of landing it all at once. That's the Intermediate one, and the hardest of the three. Lead is the surprise — a single-note melody that never leaves the bottom four strings or the first seven frets, rising for three eighths and falling for three in each of the first three bars. Then bar 4 stops rocking and falls the whole way home.
Work all three and you come away holding the accompaniment, the voicings and the melody for the same piece of music. Go straight through in order, or take whichever part fits your week.