"Hmm, yeah. How about I tie a rope around my pack and pull it after me so it's not on the bridge at the same time?"

"Good plan!"

He suits action to words and sets off with some trepidation across the bridge that hasn't had anything messed up happen to it (yet).

This goes fine!

"All right," says Speeba, "who's next—"

"I'll go," says Kwispafa, rolling up to the same bridge their ammi safely crossed.

Kwispafa meets the same fate as Nawu!

"Okay," says Speeba, "these are the Lands of Logic, not the Lands of Arbitrary Misfortune, what's the puzzle here—Kwisp, can you try the other bridge—"

Kwispafa wiggles back up onto their wheels and retrieves their tiny share of the party's supplies and rolls determinedly across the north bridge. This time they pass without incident.

"Suggestions, anyone?"

"Maybe we need to go north and south in a specific pattern? Or there's something about Speeba that means they can take the south bridge and nobody else who's tried can?"

"Could be age, could be—I was going to suggest it was the wheels but Kwispafa got sneezed so not that—hmm—Raclie, try the north bridge—"

A Zoombini with flat-topped hair and glasses and a red snoot and a propeller proceeds cautiously across the same bridge that Nawu, Bruce, and Kwispafa have all safely crossed. They manage it too.

"Okay," says Speeba, "youngest then oldest then youngest again, keep trying the north bridge until something happens."

The next littlest Zoombini after Kwispafa trundles up to the north bridge on their skates. Their hair is a tiny tuft, their eyes are small like Speeba's, and their snoot, like Speeba's, is yellow.

This time the north face sneezes, with a great "Ah . . . ah . . . ahCHOO!" that sounds like a gale howling through a cave and throws the next littlest Zoombini to the grass in a heap. The bridge support is looking noticeably the worse for wear.

"You okay?" says one of the grownups on that side, helping the little orb get back up on their skates.

"I think so!" they say, a little shaken but mostly determined. "Should I try the other bridge?"

The grownups on that side look across the ravine to Speeba for their take. Speeba rolls back and forth, deep in thought.

"If I think about this like a puzzle someone set up on purpose, rather than a natural phenomenon, maybe you need to sort by appearance or something? Can cliff-heads even tell what people look like?"

"Zampaimo and I both have small eyes and yellow snoots... Vapa, try the south bridge."

A small-eyed green-snooted Zoombini starts walking across the south bridge.

Vapa reaches the other side un-sneezed-at.

"Well. That's fairly straightforward. All right, small eyes to the south, everyone else to the north, let's see if this prediction holds."

It does! The other two adults are the last to cross, but they both make it safely to the far side.

"Right!" says Speeba, with a cheery little bounce. "We made it! Let's keep going and see how far we can get before we have to make camp!"

The sun climbs toward noon and a light breeze blows through the hills. In time the party comes to a rocky ridge too steep and unstable to climb over, but with a group of four tunnels running through it. Sitting between the tunnels are four boulders with faces even more obvious (but less human) than the cliffs. They stare judgementally at the group. Then one of them opens a mouth-crack and says, "They're blue!"

"...yes we are," says Speeba, perplexed and a little wary. "Is that a problem?"

"I must be careful about who I let in. Blue skin is not necessarily unacceptable, merely . . . unconventional."

Speeba's small round face takes on a mildly disgruntled expression.

Bruce doesn't think much of these folks either, to be honest. "Do you have an opinion on humans?"

Much darker looks from all four rocks. 

Okay, wow, hopefully they just think he's weird and this is not the reputation humans have everywhere on this continent. "Does someone want to try one of the paths."

Speeba rolls up to the one on the left.

Once he's on the path leading past her, she says "Sure."

And when he reaches the top rock, she chuckles happily. Speeba gets into the tunnel without incident.

Nawu volunteers next, and follows Speeba up the leftmost path.