Logic Masters Deutschland e.V.

The toddler is a 4x4 sudoku pack exploring the new coordinate arrows constraint. It was created by Aaronymous, Piatato and myself, huge thanks to Playmaker6174 and Kafkapharnaum for testing the whole pack.

The toddler is also a story which you can follow right on this page, or in a separate PDF file.









Part I. - Unexpected Companion

"Wanna play a game? My grandma made it for me." Said the toddler. "Here are the rules". He handed me a tiny piece of paper.

"Digits on an arrow spell out the coordinates for the digit that is their sum. The row number is written on the start of the arrow, the column number is written on the arrow tip."

He smiled.

"All the arrows must correspond to different coordinates. Digits may repeat on an arrow if allowed by other rules."

The toddler smiled again and asked if I had any questions. I had none.

"And of course normal sudoku rules apply. Will you remember all that?"

"Fill in the grid with digits one to four, no repeats are allowed in any row, column or a box." He smiled once more. "Just to be absolutely sure".

I looked at the piece of paper and realised I’m in trouble.

"So, what are you waiting for?"



I gave him the piece of paper with the finished grid. "That was like taking candy from a baby", I said in an attempt of a joke. The toddler started to smile and surely enough took out a piece of candy from his pocket. "You can try to do that if you want."

We looked at each other for a moment. "Just kidding". He started to unwrap the candy. "Also, it’s another puzzle."

"Digits must increase along the thermometer starting from the bulb end".

I wasn’t sure what he was talking about, but then I noticed the little thermometer-like shape in the puzzle.



I looked at him and noticed he had a couple more puzzles in his tiny hand.

"This time every row, column, and irregular region must contain the digits 1-4 with no repeats."



"And now you must find the regions by yourself."

"Both cells on an arrow must be in the same region as their corresponding sum, that should help you."



The toddler seemed to enjoy it a lot and I have to admit, I kind of enjoyed it too. "But that’s getting absurd, the arrows point outside the grid."

"Well, the clues outside the grid are sandwich clues, they show the sum of the digits sandwiched between 1 and 4 in the corresponding row or column."

"So just in columns in fact."



"Ok, and what exactly is that?"

"Well, sudoku rules apply to both 4x4 grids sharing one box. And for each arrow the sum must be placed on the coordinate in both grids."



It seems the toddler finally ran out of his funny little ideas.



"No arrows this time?"

"You know, at some point in life you will see no way forward, no direction where to go. You will move no further until you realise you’re given all the signs, only that there are none."

"Well, I really don’t know what you are talking about, but this one looks like a little pirate. You know, with a tiny eyepatch."

"All arrows are given in this one. Which means no arrow can be added to the grid in such a way that it would be valid for the finished solution of the puzzle."





Part II. - On My Own

"Treat each digit in the grid as a building of that height."

"Having a philosophical one again?"

"The clues outside the grid give the number of buildings seen along that row or column in their direction, taller buildings hide shorter ones."



"Now, you should be able to go by yourself. Good luck. I will join you again when you need me."

"Whatever, I solved this one already anyway."









"How nice of you to choose a sandwich for your last meal."

"Eh, what?"

"So just don’t forget, the outside clues show the sum of the digits sandwiched between 1 and 4 in the corresponding row or column."

"I got that by myself. But thanks."



"And I remember this one too."

"Memories fade with time, so just to be sure. For each arrow the sum must be placed on the coordinate in the same grid as that of the arrow."

"Wait, I’m pretty sure it was for both grids last time."

"I bet you are."



"And now comes the last one."



"I little bit tiny for the final boss, don’t you think?"

"And you forgot the penpa link too."






"Are you happy now? You know, perhaps you were playing too many video games, my friend, in life there’s no fireworks in your final battle. And nothing that you've learned on your way there will help you to fight it."

"Oh and by the way, instead of usual digits 1 to 4 any set of four digits from 1 to 9 can be used in this last and final puzzle. Which four digits is for you to find out. Good luck!"