Has anyone seen a text notation for describing a Tangram solution? I'm thinking of something like chess notation or Trevor L. Davis's piecepack notation.

For example, it would need a way to describe the position of each of the seven pieces in each of these 13 problems:

Tangram solutions

  • $\begingroup$ Do you need an 'easy' notation that only works if the corners are in 'grid positions' like all the examples above, or a generic solution? (I have seen neither) $\endgroup$
    – Retudin
    Commented Sep 11, 2022 at 17:43
  • $\begingroup$ An easy solution might be enough, @Retudin. If I need something generic, I might be able to extend it. $\endgroup$
    – Don Kirkby
    Commented Sep 12, 2022 at 5:13

1 Answer 1



Full notation: write the position of all corners.

Short notation: write the position of the sharp corners clockwise; use any two adjacent corners for the square, start with the parallelogram if the long edge follows the sharp corner, otherwise end with it. (Note that the short notation requires that the reader knows the 2 rules, and the square and parallelogram can be written in 4 resp. 2 valid ways).

Example (top left): {2,3;4,4} {2,2;0,0} {0,4;2,2} {1,3;3,3} {1,3;0,4} {3,4;2,3} {1,3;1,4}

(Note that in the short notation, the interpunction is not needed. But it makes it much more readable)

  • $\begingroup$ How are you defining the origin and unit length? $\endgroup$
    – bobble
    Commented Sep 12, 2022 at 14:00
  • $\begingroup$ I did not. Enlarging, moving, or rotating the entire set gives the same solution. If easy comparison between notations is needed, you could define the position and size of an unique piece ( e.g. the square as {0,0;1,0;1,1;0,1} ) as an additional convention (and then even leave that piece out in short notation.) $\endgroup$
    – Retudin
    Commented Sep 12, 2022 at 15:04
  • $\begingroup$ PS Then using the middle-sized triangle is o.c. better then using the square. This prevents the effect of multiple solution due to the square's symmetry $\endgroup$
    – Retudin
    Commented Sep 12, 2022 at 15:13

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