How strong is the plastic once Doodled?
The flexibility and strength of your creation is really up to you. To make stronger Doodles that are able to act as supporting structures, or withstand active play, make pieces thicker by going back and forth over the same area, or Doodle very slowly to make a thick strand that will be less flexible.
If you move the pen faster and Doodle thinner strands of plastic, you will make flexible pieces. While still not easy to break, they won’t be able to support the weight of other objects.