

My wild guess on how they do that industrially is macerated pulp in water and a big nasty press to squeeze the water back out. Maybe some really cheap adhesive goes in there too, I don’t know.
For arbitrary molding, you need a certain level of fluidity that will be hard to achieve with a fairly pure pulp. You’ll notice all those packaging materials - or at least the ones I can think of - are shaped to be suitable for stamping. However, it can be used as reinforcement in concrete or a resin!
You can devise a task it couldn’t have seen in the training data, I mean.
Obviously, that goes for the natural intelligences too, so it’s not really a fair thing to require.