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Hotaru Beam Puzzle: Is it impossible?

Puzzling Asked by niak on February 1, 2021

I saw this puzzle on Twitter by user @lilva_0419 and I personally feel that it is impossible to solve. Can you prove me wrong (or right)?

Source on Twitter

Try it online

Hotaru Beam puzzle from external source.

Rules (see Wikipedia):

  1. Connect every white circle with lines into a single network.
  2. Lines start at black dots and end on white circles (not black dots!)
  3. Lines can make 90 degree turns, but cannot intersect or branch off of each other.
  4. The number in the circles gives the number of turns the line (starting at this circle’s black dot) makes before reaching a white circle.

[Begin Edit]
Here is the actual wording of the rules from Wikipedia. This is just for future reference, the accepted answer is correct, but this should clarify why the creative "think-outside-the-box" answer by FibS would unfortunately not work here. I apologize for my unfortunate wording.:

  1. Draw a line from each white circle’s black dot to another white circle, following the grid’s horizontal and vertical markings.
  2. Lines cannot be drawn from a black dot to another black dot, nor can they be drawn from a white circle not at its black dot to a white circle not at its black dot.
  3. No crossing or branching of lines is acceptable. At the end, the drawn lines will connect all white circles to form a single, contiguous network.
  4. The number on the white circle dictates how many times the line you draw ”’from its black dot”’ must bend before it meets another white circle.
    [End Edit]

[Begin 2nd edit] Apparently the Wikipedia translation of the first rule now reads (emphasis mine):

Draw a line from each white circle’s black dot to any white
circle, following the grid’s horizontal and vertical markings.

Thanks @edderiofer for pointing it out.

[End 2nd edit]


I see two options for me being wrong: I misunderstood/forgot a rule. Or I overlooked a possibility in the puzzle.

The reason I think this is impossible:

Figure 1: Part I of the reason I suspect the puzzle has no solution.

Figure 2: Part II of the reason I suspect the puzzle has no solution.

2 Answers

Well

so you could do

Full solution

(The "Try it online" link agrees that this is legal)

Answered by Lukas Rotter on February 1, 2021

Here's a solution that complies with Wikipedia's rules:

Answered by Fax on February 1, 2021

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