Newton's Hat
(Published on 22. March 2023, 18:21 by shadow-nexus)
Isaac Newton pulled a lot of things out of his hat during his lifetime, including his laws of motion that elegantly explain how things move and accelerate. Classical Newtonian physics holds a lot of historical gravity, but it is also the giant whose shoulders are the stepping stone to more complex physics.
This puzzle is a classical variant to my more complex (and more interesting) Schroedinger's Hat puzzle.
Solve
Rules
| Sudoku | Fill the grid with the digits 1-9 so that no row/column/3x3box contains repeated digits. |
|---|---|
| Arrow | Digits along an arrow sum to the digit in its circle. |
| Thermometer |
Grey paths are "thermometers" on which digits are increasing from a bulb towards the tip, or from one bulb towards the other bulb.
For thermometers having 2 bulbs, one bulb contains the lowest digit and the other bulb contains the highest digit. Each grey path starting from the same bulb is a separate thermometer. |
| Kropki |
Cells separated by a black dot contain values in a 1:2 ratio.
Not all dots are given (i.e., there are no negative constraints). |
Solution code: Row 5 and 6. (18 digits, without spaces)
Comments
on 24. September 2025, 01:59 by shadow-nexus
Removed some confusion in the rules.
Created this puzzle in SudokuPad
on 30. August 2025, 21:52 by DiMono
Typically, thermometer bulbs are never the highest digit of the thermo. It is unintuitive for that to be the case - I spent about an hour thinking that the lower thermometers all increased from bulbs and that they could meet in the middle with a high digit (i.e. the thermo from R9C3 to R9C7 could be 38752, both increasing towards the 8).
I think this would have gotten more solves if you made it clear that in thermometers with two bulbs, one of the bulbs is the high end, and the digits increase from one bulb to the other.
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RE: I'm sorry about the confusion. I took your advice to heart, and clarified the rules.
I also added a SudokuPad link where the thermometers are visually more distinct, hoping to further remove the confusion.
on 27. March 2023, 16:07 by shadow-nexus
I rephrased the rules about thermometers to make it more clear that the "hat" consists of multiple thermometers, each with their own direction.
