I really wanted to do this class even though I don't own Photoshop. So, I went through the same basic steps using Procreate. This first example is using the watercolor image Rebecca provided. I removed each stripe from the background and then warped/smudged the seams a bit.

Here it is at repeated smaller still:

In my second example, I used Procreate to make the stripes as well using some fun watercolor brushes I had bought. Using drawing assist was able to make them fairly straight and then used the same warping/smudging to make the repeat come together.

Repeated even smaller:

So, good practice even without Photoshop :)