I transpose the source code, you transpose the input!
Python 3 + numpy, 45 bytes



lambda\
a:a
ma= """
b.    "
dT"   "
a "
\ """


Try it online!

Thanks to @EriktheOutgolfer pointing out a bug of the previous version

Transposed:



lambda\
a:a.T  
ma= """
b     "
d "   "
a "    
\ """  


Try it online!

The functions take a numpy matrix as input and output a numpy matrix. The solution does not rely on comments like many other solutions do but instead exploits multi-line strings.