Ha just for fun, I did make a beaded collar for one carto and attached some jump rings to it for fun so I could in the future attach a lanyard if I felt like it. This is pretty, but not very practical, but it gave me a really good idea for a second attempt at possibly something color coded. I already know what my favorite flavors are and I can color code a collar to represent those flavors... coffee, absinthe and black licorice.
I think the next one I try will be a little less dimentional and more flat. This is pretty with the Swarovski crystals but not very practical. I'm pretty surprised by how snug it sits on the cart though, it doesn't slide off very easily!