The bamboo calligraphy pen is one of the oldest tools of calligraphy in the world.
Arabic calligraphers found bamboo to be the ideal tool for a wide variety of calligraphic works, both large- and small-scale.

Billy bamboo also has a suppleness and flexibility that is crucial for Arabic calligraphy.

Billy bamboo is the flat-sided species of bamboo preferred by calligraphers for generations. This species is both entirely different from the standard full-round bamboo.
 
Indonesian bamboo.