How can be column incluted into rows?

Question

There is the table in MS Excel or LO Calc.

How can be it converted to this view of the table?

The transformation using links (within the same table) to the initial version is allowed.

Answer 1

If you have Microsoft 365, you can come close with:

=TEXTSPLIT(
    TEXTJOIN(
        "|",
        ,
        SORT(
            TOCOL(
                TOROW(A2:A4) & "~" &
                    TOCOL(B1:D1)
            )
        ) & "~" & TOCOL(B2:D4)
    ),
    "~",
    "|"
)

We use the TOROW and TOCOL functions to create a Cartesian Product of the rows and columns, connecting each crossjoin by a delimiter. We then join the resultant single column with a different delimiter. Finally, we split the rows and columns using the TEXTSPLIT function.

The Formula Evaluation tool will help you see what's going on.

But, to not show the "duplicates" in the first column of output, you need to use conditional formatting using a formula to see if the content matches that of the row above. If it does, then format the font color to be the same as the background color.