Sadu is an old handcraft that Bedouin women practice in the Arabian Peninsula. It is the weaving of threads made from sheep wool, camel hair and goat hair. The woman spins the threads and dyes them with colors taken from plants. Then she weaves them on a horizontal loom that sits close to the ground. With this cloth she makes tents, rugs, sitting cushions and covers for saddles. Many families are proud of the old pieces that they keep. The woven patterns carry signs from the surrounding environment, such as mountains, roads and stars. UNESCO has listed Sadu as intangible cultural heritage. So interest in it has grown, and so has interest in teaching it to new generations.

Question: From what source do the colors of the threads come, according to the text?