South is a dense forest where most of the sunlight is blocked out by the canopy; what filters through illuminates colorful mushrooms and carpets of moss. Over the next few hours, the route they're on goes from "the direction the undergrowth is most manageable" to a trail to a path to a cart-track with what looks a lot like tire tracks in it.

"I don't think I've seen a wheel with a tread like that before," Speeba remarks.

"There's vehicles with tracks like that, back on Earth. Or I suppose it could be another group of people with wheels but they design them differently."

The tracks stick with the path they're on until they emerge into a clearing featuring a much more inhabited-looking campsite and a set of wooden bleachers on which are sitting . . . some folks. They have conical chartreuse bodies and technicolor hair and a similar collection of eyewear and footwear/foot alternatives as the zoombinis, albeit with a very different aesthetic. When they spot the Zoombinis, they start muttering in something that's about as unlike Islish as Shakespeare is unlike modern English, but in the opposite direction re: what sort of social class it sounds to American ears like it's signaling. Something about making sure everyone is correct in some unspecified manner.

Bruce's main reaction is "wow, alien Senior House," but nobody will get that reference so he just hangs back and lets the presumably more normal-looking Zoombinis take the lead on saying hello.

Speeba rolls closer to the bleachers and addresses the ...folks.

"Hello. I hope we're not interrupting. Do you mind if we pass by?"

One of the green folks at the top of the array, close to where three of them have eschewed the bleachers in favor of a nearby tree branch, pipes up. 

"If going yinz be through Fleen territory, doing yinz must a radical puzzle before! Got yinz-we a bitchin opportunity herenow!"

"...all right, what's the puzzle?"

"Matches each of me-us one of yinz straight across! If find yinz the ones of yinz who matches them the ones of us-we who sit us-us on the branch, will get you safe passage and a fun surprise! . . . Matches nobody the tall strange one. Confused they us-us."

"They're pretty strange," Speeba acknowledges. "All right." They roll back toward their own group.

"So if each one of us, Bruce excepted, matches a single Fleen, what does that say about correspondences?"

Bruce is very amused about being the tall confusing one and also fascinated by the Fleens' grammar. 

"Presumably it's about your features again, which is why they couldn't come up with one for me. 'Straight across' suggests it's, like, hair for hair and eyes for eyes and so on? So let's figure out how many of each hairstyle we've got . . . four four three three two, and it looks like they've got the same distribution." Being tall enough to see the whole group at once is very handy.

"Maybe the best way to do this is for everyone to check how many people here with each of their features and memorize the resulting string of four numbers, and I'll get strings of four numbers for each Fleen?" 

"Sounds good, let's make it happen," says Speeba.

With the four adults helping to organize the counts, everyone is soon supplied with a string of numbers. Kwispafa bounces in a steady rhythm while whispering to themself, "Three three four three..."

"First one is three, two, four, . . . five." (This matches Awoowoo's numbers.)

Awoowoo comes forward.

The Fleen thus indicated goes "Yaaaaa!" and leaps down off the tree branch and rolls at Awoowoo on their tank treads, attempting to herd them back around toward the other side of tree. "Now go you onto the tree! Will have you a good view up there!"

"If you say so," says Awoowoo, somewhat dubiously, and up they flutter to the indicated branch position.

The other two get matched up similarly.

As soon as the third Fleen jumps off the tree branch, the branch's bouncing up and down jostles the beehive hanging under it, and bees swarm out. The swarm assembles into the shape of a giant pair of scissors and chases all the Fleens off into the woods, paying no attention whatsoever to the Zoombinis. The Fleens vamoose, cackling gleefully (or perhaps beefully).

". . . Yay?"

"Well, we solved it," Speeba says practically. "Come on, let's see what's next."

"Three three four three," Kwispafa is still whispering with fierce concentration, until Awoowoo comes down from the tree and gently bonks against them. "What? Oh, is the numbers game over now? But I didn't even get to use my numbers!"

"That's life, kiddo," says Awoowoo. "Maybe we can think of a different numbers game to play once we make camp for the night."

"Hmm, how about you tell me what your numbers add up to? And the mean and median, if you know those?" That'll give him time to come up with a better game, at least, and has no moving parts that can interfere with ducking under tree branches.

"Three three four three adds up toooo... three and three and three is nine, and nine is ten less one so nine-and-four is ten-and-three is thirteen!" the little orb declares triumphantly. "...what's a median?"

"A median is . . . hmm, three three four three is kind of an inconvenient example. Suppose you have the set of numbers two three nine eight five. The median is the number that's in the middle of you put them in order. So for two three nine seven five, the median is five, because it's bigger than two and three but smaller than seven and nine. Does that make sense so far?"

The underbrush is getting thicker. Bruce moves up to the front and stomps a pathway, feeling amusingly like some kind of giant city-smashing monster.

"So if you put three three four three in order, that's three three three four," muses Kwispafa. "...that has two middles. Luckily both of them are three!"

"Exactly! When the two middles are different, the median is halfway between them. So if you have two four six eight the middle numbers are four and six and the median is five!" Stomp stomp crunch stomp yank shoelace out of entangling plant stomp stomp.