There's 3 strings. I've seen a higher quality HD version of this movie and you can clearly make out 3 strings in certain shots. Edit: Re-looking at this movie,

There's 3 strings. I've seen a higher quality HD version of this movie and you can clearly make out 3 strings in certain shots. Edit: Re-looking at this movie, there may be 4 strings attached, see at about 1:35 in the video at max resolution. 2 sets of 2 strings (one for each corner of the phone?)