I wonder if we have any wavelengths in common. Maybe red (the color with the lowest wavelength that humans can see) is “♪♫♩,” the highest wavelength they can see. Or something. Might be worth looking into. I should bring a rainbow of lights in and find out if he can—oh, he’s back.

Rocky bounces into the tunnel and spider-walks along the rails to the dividing wall. He’s incredibly graceful at it. Either he’s very seasoned at being in zero g or Eridians are just really good at climbing around. They have five hands with opposable fingers, and he’s an interstellar traveler, so it’s probably a little bit of both.

With one of his hands, he holds a device up for me to see. It’s… I don’t know what it is.

It’s a cylinder (man, these people like cylinders), a foot long and maybe 6 inches wide. I can see that his grip deforms the casing a little bit. It’s made of a soft material, like foam rubber. The cylinder has five horizontally aligned square windows. Inside each window is a shape. I think they might be letters. But they’re not just ink on paper. They’re on a flat surface, but the symbols themselves are raised an eighth of an inch or so.

“Huh,” I say.

The symbol on the right rotates away to be replaced by a new symbol. After a couple of seconds it happens again. Then again.

“It’s a clock!” I say. “I showed you a clock, so you showed me a clock!”

I point to my clock, still taped to the wall, and then to his. He does the jazz hands with two of the hands he’s not using at the moment. I do jazz hands back.

I watch the Eridian clock for a while. Rocky just holds it in place for me to see. The symbols—numbers, probably—cycle through on the rightmost window. They’re on a rotor. Like an old-school digital clock back home. After a while, the rotor one step to the left of it changes one position. Aha!

As far as I can tell, the right rotor changes once every two seconds. A little more than two seconds, I think. It cycles through six unique symbols before repeating: “ℓ,” “I,” “V,” “λ,” “+,” and “V,” in that order. Whenever it reaches “ℓ,” the next rotor to the left advances one step. Eventually, after about a minute of this, that second-from-the-right rotor works its way through all the symbols, and when it reaches “ℓ,” the third rotor from the right advances.

Looks like they read information from left to right—same as English. Neat coincidence. Though not incredibly unlikely. I mean, there’s really only four options: left to right, right to left, top to bottom, or bottom to top. So there was a 1 in 4 chance we’d be the same.