You could achieve this look by piping with royal icing... just an idea...
I had a look at the link suggested by keepingitreal21 - perhaps this string effect design could have been made using an IMPRESSION MAT???
Hope this helps!
Get an extruder. Squeeze out your strings and apply them to the cake while you have someone turn it on a turntable.
It clearly says in the link that the cake was covered in fondant then the strings were applied to "give the ripple effect".
You could do the 'strings' by hand, but I'm assuming you'll want the cake sometime this year. It would take me that long by hand, lol , but with an extruder and an extra pair of hands for the application, easy peasy. The trick will be deciding the correct diameter for your strings. Too small and it will look like wrinkles in your fondant, and too big and you lose the elegance of the original.. HTH
and the marcato pasta rollers have spaghetti and fettuccine settings too
maybe easier on the hands/wrists
what a gorgeous cake