I first heard about Tapa cloth on a visit to Tonga, where my parents lived for two years. The women in South Pacific countries (like Tonga and Samoa) cut down mulberry trees (3 inch in diameter), strip the bark, soak the bark, strip the inner bark and then pound out the fibers with wooden mallets against a flattened log. This widens the strips, but thins them enough that a second layer of bark fibers need to be pounded together for strength.
These strips are later combined, with a tapioca flour paste, with other strips to make a larger cloth. Long tables with a village's traditional pattern carved into the top allow the women to do rubbings with brownish pigment.
Geometric patterns, or organic symbols such as flowers or turtles are common. I used this assignment to bring some south pacific culture to a lesson on ART PRINCIPLE: repetition/pattern. It also kicked off our unit on TEXTILE ARTS.