Piano hinge binding

This past weekend at the Memory Bound crop I ran into my friend Robin and she had seen this amazing creation and wondered if I had ever done a piano hinge book. I have and this is the book I have that taught me how, by Design Originals.

Here is a small piano hinge book I did, it's been probably at least a year or so ago that I did it. It's not very big, 4.25 5.5.

I think I intended it as a garden journal type book, but I never got that far with it!
I used bamboo skewers. It's actually relaxed over time, I think I bound the string at the top and bottom a little tight and it used to stay sproinged open, but today it is sitting very nicely, non-sproinged!