Origami Slinky – non modular version

This new version of my origami Slinky can be folded from a single long strip of paper (you can use register or calculator rolls for example). In theory it can be as long as you want, but in practice it is difficult to keep the precision after folding many levels of the spiral.
See also the modular version: https://www.youtube.com/watch?v=2ErCU013v0k

Designed by Jo Nakashima (03/2018)
Difficulty level: low intermediate
My paper: Thermal paper roll 8cm wide (receipt, adding machine, register or calculator Rolls). For a 8cm wide strip, each lap will use 20cm. My slinky has 15 laps, so it is 15×20 = 300cm long
PDF diagrams: not available