Bb Power Chord (Bb5) on the guitar fretboard
The Bb Power Chord (Bb5) is made of Bb (the root) and F (perfect fifth). The fretboard shows every one of them across the neck in standard tuning (E A D G B E), and plays them back so you can hear the chord.
The power chord is only a root and a fifth, with no third to say whether it is major or minor. That leaves the shape two notes wide and easy to slide along the neck. Add a third above it and it becomes one of the triads.