Piano Bag for piano books

I made this piano bag for Sophia to carry her piano books to piano lessons. She wanted a backpack.  

I decided to make it a backpack which converts to a cross body and or tote bag.  She absolutely loves it and can't wait to take it to her lesson.

I had to figure out how to secure the single strap but provide enough support to carry the weight of all the music books she has. This was the result. Here the strap is fully extended for a tote bag,

Here the bag is slid through the support strap which changes it into a backpack.

The inside is fabric printed as sheet music.

Here is another view of the tote bag piano tote I designed and sewed. The tote is large enough to hold piano books which are larger than a normal book or notebook.  No pattern was used in this design.  This is my own original design.