[threefinger]

"trivia:what is the plank made of, and when did it change???

It's unspecified, or as termed in the TR, "free."

TR 3.5.9-h:

"The material of the plank is free, but it must be homogeneous with a specific gravity between 1.3 and 1.45"

Before the Senna crash it was made from a wood composite called "jabroc." Now the most common material is a glass-reinforced composited called "permaglass."

[Chode]

permaglass yup, winner...