They entered a room filled with glass beakers and bubbling liquids, with little Bunsen burners in a row and large machines making chugging noises. The room was hot and smelled of strange chemicals. Oliver wrinkled his nose at the stench.

You may have heard the rumors, Armando said, that nothing I invented ever worked.

Oliver felt bad for the old man and blushed on his behalf. Yes, I did hear that.

Armando nodded sadly. They took my team away. Sent them elsewhere, to places theyd be more useful. They closed the factory. Officially anyway. I continued to work here secretly.

The secret wall! Of course. No wonder this wing of the factory was so odd and hidden away behind the mechanical wall. Armando had had to conceal himself, to keep his work undetected in order to keep going.

So youve been alone here ever since? Oliver asked.

Unfunded would be a better word, Armando said. He sighed, as if there was some kind of heavy weight pressing on him, and tapped his skull with a bony finger. I have so much knowledge in here and no one to pass it on to. No son or daughter. No apprentice.

They drew up slowly to a machine. It was just like the large bowl-shaped invention Oliver had first seen in the main factory. But while that one was covered in dust and falling into disrepair, this one looked brand new.

Oliver touched the brass mechanism with his fingertips.

I call that a Birds Eye View, Armando said.

What does it do? Oliver asked.

It allows you to look down from above at certain locations. It was supposed to help with reconnaissance during the war effort.

Oliver frowned. But how does it work? Youd need cameras in the sky. And whats the bowl for? And this spinny bit? I dont understand.

He mulled it over. Perhaps it was something to do with electromagnetic currents passing through the raindrops in clouds, causing some kind of image in much the same way as an ultrasound, or how blind bats use sonar to see. But even that was too out there for Oliver to accept. Really, the only way something like that could ever work was through some kind of undiscovered physical force. Some kind of magic.

Armando let out a morose smile. It never did work. There was always a missing ingredient. With every single one of my big inventions, there was always just one thing missing.

Oliver wondered what Armando meant by that. What could the missing ingredient he was alluding to be?

He realized then that Armando had carried on ahead. Oliver rushed to catch up.

So youve been making inventions for seventy years? he asked.

And counting, Armando replied.

They didnt send you to fight after they shut down the factory?