When I started to play electric guitar I used Youtube backing tracks to play along. After a while of jamming I had my tones which sounded nicely with the song. But, after a certain time these tones were forgotten and I had to start from scratch again.
In doing so I started over with the high E-string and discovered my tones on the first 15 frets, second the B-string and so on. Finally, I knew how to play some double stops combining these strings.
This was the birth of Sfive:
+ Create a song.
+ Save your tones on a virtual fretboard.
+ Hide or show single strings on this fretboard.
+ Start Youtube backing tracks in the background without switching between the apps.
Since each song has it's core tones Sfive limits the number of tones per song to five at maximum, but, shows these tones in all positions.
If you want to play a song discovered on guitar on the mandoline or bass guitar or vice versa Sfive allows to switch between these instruments as well.