When I was about 12 years old an uncle gave me his mandolin as he no longer played it at home as his wife felt it might frighten their new baby and so I started going to lessons and was soon able to play exercises and simple tunes. I'd often used to make up melodies in my head or sing them with made up words but now that I could read music and had an instrument that I could play I was able to work them out in detail and write them down. I made up a piece for 2 mandolins that I called the Dance of the 2 Little Sprites. I've always been able to carry 2 or more tunes in my head at once but of course I could only play or sing them one at a time. However I took this piece along to my mandolin teacher to play along with me and she did though she didn't say it was good or bad, only that it's a nice hobby. I always remembered it and latterly used it as the basis for the third movement of my string quartet.