Room 13 have created colourful truffula trees

The truffula tree is based on a real species of tree in Elliot's house that Dr. Seuss saw when he traveled there with his first wife.

In The Lorax Dr Seuss writes that the truffula trees have yellow or white-and-black striped bark and a large tuft at the tops which can be knitted into a Thneed. This tuft is typically a warm color, commonly red, orange, yellow, pink, or purple (which is rare). Truffula trees apparently give off the smell of butterfly milk. The tufts which are furry to the touch apparently are "softer than silk."