Originally Posted by: jggonzalez230I am diving deeper into theory and practical application on the guitar. Right now I'm focusing on learning how to harmonize lead lines with 3rd and 6th intervals. My issue is that I'm a very visual learner, so I would like to see some diagrams.

That's an interesting observation. I've done tutorials on guitar harmony (including 3rds & 6ths), but the patterns are all in the notation or tab.

https://www.guitartricks.com/tutorial.php?input=1965

https://www.guitartricks.com/tutorial.php?input=2000

https://www.guitartricks.com/tutorial.php?input=2014

https://www.guitartricks.com/tutorial.php?input=2121

You might get a lot from these tutorials on harmonizing the major & minor scales.

https://www.guitartricks.com/tutorial.php?input=2387

https://www.guitartricks.com/tutorial.php?input=2393

I have this tutorial that explicitly uses 6ths in a scale pattern.

https://www.guitartricks.com/lesson.php?input=22937

There are a lot of diagrams in my collection on triads & inversions that might be beneficial. and you could probably use those to figure out the pattern you are looking for.

https://www.guitartricks.com/collection/triads-and-inversions

And this tutorial has some great images that show all the scale degrees in every possible configuration.

https://www.guitartricks.com/tutorial.php?input=462

But, the bottom line is that I don't of any fretboard images of only 3rds or 6ths! I'll make one & post it here later this weekend. :)