Chapter 1: Stranded

You awake with a shiver and the sound of lapsing waves around you. Confused, you sit up slowly. Looking around, you find yourself on the beach of a small island, stranded. Thankfully, you see your trusty backpack washed up on a rock and begin to make your way over. You take in some more of your surroundings, the white sand, the dense jungle blanketing the area inland and a distant sparkle of something reflecting the sun’s light above the canopy. It all seems rather magical.

As you start to wonder where on earth you’ve found yourself, a shadow streaks past your vision, followed by a gust of wind and the rapid thrashing of wings.

“Why hello young traveler and welcome to Andolore Island.” The voice is oddly unnatural yet warm nevertheless. You look up at the figure perched on top of the rock, stunned. Looking directly at you are the eyes of a dishevelled Toucan. “My name is Terrance the Talkative Toucan, but you may call me Terry. It seems you are stranded here with no hope of escaping unless a wise and knowledgeable King of the Jungle helps you.”

You feel as though your eyes deceive you, how can this be? “You can talk?” You blurt out, rather rudely.

“Of course I can talk, Toucan do anything they set their mind to. Now is no time to dilly dally, I’ve been waiting years for a ticket out of here, and you may be just the thing.” As you recover from your initial shock, your attention is stolen by a bright green frog emerging from behind the toucan. It eyes you intently, you half expect it to greet you too but it simply raises its webbed hand and points towards the sand.


You look down and notice a small bundle of fish spawn by your feet, still damp but isolated from the embrace of the sea. As you look back up at the frog, it points its hand out to sea pleadingly. 

“It seems this young fellow would like your help. Can you find a way of drawing a canal in the sand so that the waves can reach the fish spawn?” The frog lets out a ribbit, interrupting the toucan. “Oh yes I see. He’s already dug out some sections for you, and indicated how many canals you must dig around some of the squares. You are to dig a single continuous canal without forming any loops, forks or leaving canals isolated. Is that all?”

The toucan looks down to the frog, who responds with a short rib. Can you work out how to dig the canal?

If you need help, you might want to ask Terry for some. This help can be found here.

You may want to print off your own copy of the canal map so that you can analyse it better. You can find a printable image here. [There is no need to print in colour]



You get down on your knees and diligently mark out a small groove for the water to flow, being sure not to incur the wrath of the frog. The waves flow in and your channel works, drawing the fish spawn back out to sea safely.


Surprisingly relieved, you get to your feet and greet the frog with a smile. It smiles back at you and three more frogs leap out from the undergrowth lining the beach. Terry looks impressed, “Well done, I must say it’s taken me a long time to earn the trust of these little squirts.” You bend down to retrieve your pack and notice he has a little satchel of its own slung around his neck. In it, you notice some ripe figs and your stomach starts to wonder when it last had a meal.

“Could you spare a fig for a starving survivor?” You ask.

“Ah, now there’s a problem. Both you and I find ourselves famished, so why not feast on these fruits you may wonder? You see just yesterday I was foraging for figs when I noticed one of the branches I had plucked from looked old and withered. Forgetful as I am however, I could not recall which one of the 16 figs I had gathered came from the rotten branch. Luckily for us, you’ve just earned the trust of this island’s greatest sleuths. If one of these frogs eats a chunk of rotten fruit, their skin will turn red as lava.”

“My puzzle for you is this. You may conduct rounds of testing in which you give each of the four frogs a collection of chunks from any of the figs you choose. All four of them will then eat all of the chunks in one go and those who ate rotten fruit will turn bright red before fading back to green. Can you find the least number of rounds needed to identify which is the rotten fig? How will you assign the chunks in each round?”

“If you solve this puzzle, I will happily share these figs with you. And,” the Toucan added slyly “this dusty old map of the island-could be of use to someone in your position…”


You take some pen and paper out of your sack and give the problem a try. If you need, you can ask Terry for some help, which can be found here

Solutions to the puzzles from chapter 1 can be found here.

The story continues in chapter 2 here.

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