This is my famous 3D-TREX or 3D-REX as I affectionately call him. This dinosaur has moving arms and a moving mouth due to an internal connected structure which I designed exclusively for this model and for other future works. This structure allows the jaw to move when the arms are moved up and down and vice versa while remaining completely hidden, unlike most moving models you see on sites such as Thingiverse. Works as both a small or large print, however, the movement is much larger when the print is larger. If you print it big enough you can even let it roam your office or kids room biting the fingers or hands of anyone who comes too close. Version 3.0 is has a completely contained system and the greatest movement of any modelVersion 2.0 is less hidden and has some gaps but has less degree of motion