Keep reading and this odd picture will make sense.
Find a string around the house. Find a weight that has a hole in it. Tie your string to the weight and let it drop down onto your tile. Do this until you have a string that you find pleasing. Take a picture or get out your pencil and start drawing. TA-DA! Your own string! You can incorporate the shape of your weight into your design or not. Your choice.
Now, the string can be a variety of things; cord, yarn, thread, ribbon, beads, etc. And the weight can be a variety of things too. A washer, a heavy button, a nut from a bolt, a ring (wedding or otherwise), a fishing weight, etc. You don't have to go out and buy something. There will be something, somewhere, laying around the house.
Then you can get creative. Try thicker ribbons and twisting them, try rubber bands knotted together, I'm sure you can come up with new ideas. Then please share them with me!!!