I am a game developer working on a project and I had an idea to create the following puzzle.

There are two robotic "tentacles", each with 4 joints. The player can control some, but not all of the joints; this is by design. The player can control them by rotating the joints in $30$–degree intervals up to three times, before the tentacle returns to its original position. In addition to this, some of the joints are interconnected, i.e. moving one will affect the other.

tentacle diagram

In the diagram, the actions are not precisely what I have implemented but it should give an idea. Basically, while each button limits the joint to be moved to 4 positions, it can be in more positions if another button also rotates that joint (by interconnection), or a lower one is used which then rotates all the elements above it.

For example, rotating the closest joint on the left arm will cause the whole left arm to turn (obviously), but in addition to this, the top joint of the right arm will rotate because the two joints are interconnected.

The goal would be for both tentacles to reach particular position.

The problem is that I cannot see how to make it solvable logically instead of randomly rotate individual parts. Is there something I could follow to make it like that?

  • $\begingroup$ Hey there! Welcome to Puzzling SE. I understand how the puzzle works, but it might be helpful for others if you added a diagram. Would that be possible? $\endgroup$
    – user46002
    Commented Jan 23, 2019 at 6:35
  • $\begingroup$ Thanks! I might tweak it a bit, if you don't mind. $\endgroup$
    – user46002
    Commented Jan 23, 2019 at 6:48
  • 1
    $\begingroup$ @Hugh Of course, thanks. Funny enough, my corporate firewall blocks the image in the post, so I cannot see my own post properly :) $\endgroup$
    – John V
    Commented Jan 23, 2019 at 6:51

1 Answer 1


I think in order to force the player to use logic, rather than random moves, you need to make using logic a more attractive route than random guessing. Therefore, I'd suggest you do three things:

  1. Simplify the range of possible moves

Between complex interconnections and the shear number of valid positions, the difficulty will rapidly increase, making it hard to even know where to start with logic. I'd suggest giving each joint only 2 possible positions, which will still allow for interaction complexity, whilst allowing the player to actually hold the puzzle state in their mind and start calculating ahead.

  1. Ensure that the solution path is a relatively limited number of steps

Again, in order to use logic, you need to be able to visualise and calculate how the various interactions are going to play out. If the solution requires more than 4 or 5 steps to complete, then it's going to be unwieldy without just playing around and guessing.

  1. Only allow the player a limited number of moves

The above points should make your puzzle solvable by logic, but it will also make it even easier to just randomly mash buttons and eventually arrive at the solution. To prevent this you could have some sort of "penalty" for guessing. This could be implemented many ways such as, limiting the number of moves (device resets after N button presses), having a "cost" per move (injuring the player, reducing the reward for solving, etc), having them "sent back" (thus suffering a time/delay penalty), or some mixture thereof.


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