Well the first LEGO plastic produced for Automatic Binding Bricks (LEGO bricks from 1949-53) by TLG Billund Denmark were made of Cellulose Acetate. And anyone who has seen very old LEGO plastic can tell how much it warps. Just doing some research (...) (11 years ago, 25-Aug-13, to lugnet.general)
Whooops.... goofed on that 2nd link in the previous post... (URL) way this can be mistaken for a non-licensed clone! Cheers, Gary Istok (11 years ago, 25-Aug-13, to lugnet.general)