7
$\begingroup$

I'm wondering if it is possible to make a 3x8 grid using 6 tetrominoes: 2 Is, 2 Ls, a Z skew, and a square tetromino. I believe it may be impossible but would like to know why.

$\endgroup$
3
  • $\begingroup$ Even if the L tetronimoes are both right Ls and not a left and right L? I can't see how without flipping the tetronimoes $\endgroup$ Commented Dec 6, 2023 at 19:58
  • $\begingroup$ Can you please give an explicit definition of the tiles, or if those are standard, a link to a description? $\endgroup$
    – Plop
    Commented Dec 7, 2023 at 8:52
  • $\begingroup$ @Plop - They are standard names, I've added a link to the wikipedia page $\endgroup$
    – fljx
    Commented Dec 7, 2023 at 9:05

3 Answers 3

8
$\begingroup$

It is

possible:

    1 1 2 2 2 2 3 3
    4 1 1 5 5 5 3 3
    4 4 4 5 6 6 6 6
 

Without flipping an "L":

    1 1 1 1 2 2 3 3
    4 4 5 5 5 2 2 3
    4 4 5 6 6 6 6 3
 

$\endgroup$
4
  • $\begingroup$ Thank you. I can't seem to make that one myself I think my L shapes are orientated differently but using your answer I have made the following $\endgroup$ Commented Dec 6, 2023 at 19:50
  • $\begingroup$ Problem I have is my L tetronimoes are both of the form of 5 and not 4 so I can't create a grid $\endgroup$ Commented Dec 6, 2023 at 19:53
  • $\begingroup$ @JohnWilliams That's possible, too, see updated answer. $\endgroup$ Commented Dec 6, 2023 at 20:05
  • $\begingroup$ Fantastic. Is this unique or is there another that could be formed? $\endgroup$ Commented Dec 6, 2023 at 20:10
6
$\begingroup$

All the ways it can be tiled. Five ways, if you want to search by hand... Two ways use a mirrored pair of Ls. I have a program that does this sort of thing, started writing it when the IBM PC was released so it's out of control now in terms of code length/maintainability.

enter image description here

$\endgroup$
3
  • $\begingroup$ You should note that only one of those uses two Ls and a Z. The flipped versions of these are J and S. $\endgroup$ Commented Dec 7, 2023 at 13:18
  • $\begingroup$ @DanielMathias Since OP referred to 'tetrominoes' not 'one-sided tetrominoes', I take 'L' to mean 'L or it's mirror'. This is the generally accepted terminology. Of course I accept that OP might have intended it the way you said too... $\endgroup$ Commented Dec 7, 2023 at 17:29
  • $\begingroup$ OP's comments indicate one-sided tetrominoes. That's why I suggested the note. $\endgroup$ Commented Dec 7, 2023 at 17:35
2
$\begingroup$

It is possible; I wrote a small C++ program to find a solution: https://godbolt.org/z/rdjb7n66s

Sample solution:

 L I I I I L O O
 L Z Z L L L O O
 L L Z Z I I I I
 

$\endgroup$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.