The first design is already symmetrical both vertically and horizontally.
In solution 2, we switch the position of the triangle design elements while we keep the top and bottom rows the same.
Solutions 3 and 4 still keep the top and bottom rows the same and switch the position of the stars and triangles vs solutions 1 and 2. Also, in these two solutions, the triangles are pointed inversely.
All other solutions have switch the figures in the top and bottom rows vs the first 4 solutions.
Also, in solutions 5 and 6, the middle row replicates the same symmetry and in solutions 3 and 4.
Finally, in the last 2 solutions, the top rows still stay the same, but the position of the triangle and star figures switch and then the triangles get reflected.
Answers to the 15-SQUARE PUZZLE
In all of the solutions, the position of the squares containing text or a QR code are irrelevant.