Down here we have all the plastics works, Lucas explained, as he walked slowly along. He pointed into one room where there was an enormous molding machine and conveyor belt. You can make anything you want in there. Just program the computer, add the raw ingredients, and let the machines do the rest.

Olivers eyes widened with excitement. Will I get to work in here?

Lucas gave a noncommittal shrug. Maybe one day. But I have an assignment lined up for you today and it doesnt involve molding.

Oliver was a little disappointed to not be able to use the cool machine, but he was sure his real assignment would be just as exciting.

In the next room, there was an even more sophisticated-looking machine. It was a 3D printer, Oliver realized.

We use this for more intricate plastics, Lucas said. All the fiddly bits.

Olivers eyes widened even more when he saw the 3D printer. Hed always wanted to try one out. Will this be part of my assignment? he asked.

Lucas shook his head. The designs are far too advanced for you.

Oliver pouted. He didnt like being talked down to, especially when Lucas knew nothing about him or his abilities. Lucas had no idea how smart Oliver was or how quickly he learned things. But again, Oliver didnt protest. Hed seen so many exciting things in the factory that he knew whatever he ended up working on today would be just as awesome.

Lucas took Oliver along still another corridor hed never noticed before. It was extremely narrow, and Oliver worked out that it must run sandwiched between the one where his own bedroom was located and the one with all the plastics machines. It was so hidden it would be easy to completely miss it, to walk right past without noticing it was there. Indeed, Oliver must have done just that himself.

Down here we have Armandos room, Lucas said. Its off limits, of course.

Yes, yes, Oliver said with a sigh. Lucas sure seemed to enjoy rubbing it in how much he wasnt allowed to know.

He looked at the door curiously, wondering what kind of room the old inventor would have and what kind of secrets he might have hidden inside.

They carried on along the strangely narrow corridor. It was quite claustrophobic and that wasnt helped by the dim lighting. But then suddenly the corridor opened up, both in width and height, and there was just one enormous door ahead of them.

Lucas stopped. Oliver did too. The door was huge and made of thick steel. Yellow and black stripes had been painted across it and the words NO ENTRY had been spray painted in red. The door looked very secure, its thick steel clearly impenetrable with any kind of cutting machine.

Armandos secret invention is kept safe inside here, Lucas said. Then he turned and looked at Oliver and repeated his favorite mantra. But its off limits to you.