Left Rock somehow launches her entire body into the air and lands with a thud that knocks Nawu off the slope. "Uh-uh," she says in a voice so annoying it would be implausible from a human, let alone a rock.

"...fine," says Nawu. They try the other side.

Nawu can get to the top right passage, which merges a few meters back with the one Speeba's in.

"I'll try next!" say Kwispafa, and they head for the same path Speeba took.

Kwispafa gets past Left Rock but draws the ire of Top Rock, who knocks them off the path and "explains" herself with "We must be selective about our clientele!"

Well, what if... they take Left Rock's other path...?

"Enjoy yourself," says Bottom Rock.

"...thank... you...?" says Kwispafa suspiciously. But they're safely past the hazard, so they'll take it.

"All right, who next?" says Speeba, peering out of the tunnel mouth. The view past Top Rock isn't great. "Is someone keeping track of the puzzle? I can't see everything from here."

Bruce is tall enough to see into all four tunnels pretty easily. "Maybe Rotheefa should try going the way Speeba did? Since you're mostly similar?" 

"Sure," says Rotheefa. Up they go.

They reach the top left tunnel unmolested. Bruce suggests Zampaima and Plora go next, with the same result.

"Hmm. There's no one characteristic that we all share... Bruce, you've got the best view of all of us, what are you seeing?"

"Well, the difference between top and bottom is either your eyes or your snoot . . .  Vapa's got Speeba's eyes and Leiwy's got Kwispafa's eyes, so they could try top left and bottom left respectively?"

The named Zoombinis make their attempts. Vapa succeeds, but Leiwy runs afoul of Bottom Rock and has to start over. "Should I try top left, then...?"

"Ack, sorry! But yeah, top left, if the one on the left was going to attack you they would have done it already. And if it's not eyes, I think it's that everyone with a red snoot goes to one of the bottom paths."

"Okay." Up goes Leiwy, and this time they make it safely to the top.

"If that's what it looks like to you, I'm happy to proceed on that assumption," says Speeba. "What about left versus right, can you find any clues about that one?"

"Nawu's the only one who's gone right so far . . . aaaaand  . . . " Bruce's eyes flick back and forth a bunch of times. "And the only trait they don't share with someone who went left is the spring!" 

"All right, everybody," says Speeba. "Let's go with that. Red snoots on the bottom, springs on the right."

The Zoombinis line up at the appropriate paths. A couple of them glance up at Bruce as though wondering which line he belongs in. Then they start traipsing and trundling and bouncing and fluttering up their respective paths, one at a time in an orderly fashion.

Everyone gets where they're going!

Bruce stares at the rocks. The rocks stare back. Bruce attempts to go up the top left path and all four rocks lose their shit, or possibly their marbles, and try to knock him off. He ends up scrambling up the slope and into the bottom left on all fours, at which point all four rocks immediately stop moving and seem to be trying to pretend nothing happened.

Bruce moves to get up, thinks better of it, and brushes himself off while squatting in the low-ceilinged tunnel. "Okay, that was kind of bogus, but I think I got away with it?"

"Looks good to me," says Awoowoo. "Let's go."

The Zoombinis all head up the tunnels to the point where they merge, and after a quick orbcount, proceed onward to see where it will lead.

It leads out into rolling grassy hills dotted with clusters of trees.

Speeba reorganizes the expedition into a suitable formation for long marches and off they go.

Bruce brushes the dust and gravel off his clothes and backpack and sets off trekking with the rest of the squad.

As midday turns into afternoon, they come to a pass between a pair of hills, which contains a contraption slightly taller than Bruce with pictures of pizzas on it, and a tree stump with a face. 

"Fleens?" says the tree stump eagerly as he hears them coming, then "You're not fleens!"

"What's a fleen?" wonders Kwispafa.