Modelling string

Hi,

I am very new to Solidworks and am designing a cat tower just to see how it looks before I decide on a final design.

I want to mimic the effect of the string by adding an appearance to a tightly wound helix, (with the final aim of making it sit around the wooden posts) but I cannot seem to do this.

Any help greatly appreciated!

Thanks, Matt 

SolidworksParts And Features