Local ende:Byte=Asc(Upper(Input()))
Local k%
For Local i%=0 To (ende-65)
    For k=0 To (ende-65-i);Write " ";Next
    For k=0 To i%;Write Chr(k+65);Next
    For k=i-1 To 0 Step -1;Write Chr(k+65);Next
    Print
Next
End

Building pyramide
Compiling:pyramide.bmx
flat assembler  version 1.68  (1255799 kilobytes memory)
4 passes, 2690 bytes.
Linking:pyramide.exe
Executing:pyramide.exe
>z
                          A
                         ABA
                        ABCBA
                       ABCDCBA
                      ABCDEDCBA
                     ABCDEFEDCBA
                    ABCDEFGFEDCBA
                   ABCDEFGHGFEDCBA
                  ABCDEFGHIHGFEDCBA
                 ABCDEFGHIJIHGFEDCBA
                ABCDEFGHIJKJIHGFEDCBA
               ABCDEFGHIJKLKJIHGFEDCBA
              ABCDEFGHIJKLMLKJIHGFEDCBA
             ABCDEFGHIJKLMNMLKJIHGFEDCBA
            ABCDEFGHIJKLMNONMLKJIHGFEDCBA
           ABCDEFGHIJKLMNOPONMLKJIHGFEDCBA
          ABCDEFGHIJKLMNOPQPONMLKJIHGFEDCBA
         ABCDEFGHIJKLMNOPQRQPONMLKJIHGFEDCBA
        ABCDEFGHIJKLMNOPQRSRQPONMLKJIHGFEDCBA
       ABCDEFGHIJKLMNOPQRSTSRQPONMLKJIHGFEDCBA
      ABCDEFGHIJKLMNOPQRSTUTSRQPONMLKJIHGFEDCBA
     ABCDEFGHIJKLMNOPQRSTUVUTSRQPONMLKJIHGFEDCBA
    ABCDEFGHIJKLMNOPQRSTUVWVUTSRQPONMLKJIHGFEDCBA
   ABCDEFGHIJKLMNOPQRSTUVWXWVUTSRQPONMLKJIHGFEDCBA
  ABCDEFGHIJKLMNOPQRSTUVWXYXWVUTSRQPONMLKJIHGFEDCBA
 ABCDEFGHIJKLMNOPQRSTUVWXYZYXWVUTSRQPONMLKJIHGFEDCBA

Process complete