Batch, 226 bytes

@set z=ABCDEFGHIJKLMNOPQRSTUVWXYZ
@set a=YXWVUTSRQPONMLKJIHGFEDCBA
@for /l %%i in (0,1,25) do @call echo %%z:~0,%%i%%%%z:~%%i,1%%%%a:~-%%i,%%i%%
@for /l %%i in (24,-1,0) do @call echo %%z:~0,%%i%%%%z:~%%i,1%%%%a:~-%%i,%%i%%

Batch, 226 224 bytes

@set z=ABCDEFGHIJKLMNOPQRSTUVWXYZ
@set a=YXWVUTSRQPONMLKJIHGFEDCBA
@for /l %%i in (0,1,25)do @call echo %%z:~0,%%i%%%%z:~%%i,1%%%%a:~-%%i,%%i%%
@for /l %%i in (24,-1,0)do @call echo %%z:~0,%%i%%%%z:~%%i,1%%%%a:~-%%i,%%i%%

Edit: Saved 2 bytes thanks to @EʀɪᴋᴛʜᴇGᴏʟғᴇʀ.