These diagrams accompany this video on the Pentatonic Scale:
Video: https://youtube.com/live/CVPHEpgXHKo
The major pentatonic scale is fundamental. You hear it all the time in music.
Yes, because it sounds nice ... but there's more to it than that. There's an underlying theory to the way this pattern is formed. (It's basically a major scale without intervals 4 and 7.)
To get a feel for how to play it on both piano and guitar, check out these diagrams in all 12 keys: