I have been experimenting with the spacing of the cuts of the hinges and the pattern they can create. The top image is of a cross pattern which has limited flexibility but is not as successful as the more simple rectangular and square cut designs.
The second image is an experimentation in spacing of one of the original hinge designs. It is apparent that it is not the simply the size of the cut that affects the flexibility, it is more about the negative space in relation to the amount of material that is left around it.
There is also the possibility to cut more rounded shapes to create hinges, but I prefer the look of the straight line and the way they work with light and shadow.