of twenty-four letters and assuming a rectangle of six letters horizontally, and four letters vertically, we may have:

(a) Simple Horizontal:

A B C D E FF E D C B AS T U V W XX W V U T S
G H I J K LL K J I H GM N O P Q RR Q P O N M
M N O P Q RR Q P O N MG H I J K LL K J I H G
S T U V W XX W V U T SA B C D E FF E D C B A

(b) Simple Vertical:

A E I M Q UD H L P T XU Q M I E AX T P L H D
B F J N R VC G K O S WV R N J F BW S O K G C
C G K O S WB F J N R VW S O K G CV R N J F B
D H L P T XA E I M Q UX T P L H DU Q M I E A

(c) Alternate Horizontal:

A B C D E FF E D C B AX W V U T SS T U V W X
L K J I H GG H I J K LM N O P Q RR Q P O N M
M N O P Q RR Q P O N ML K J I H GG H I J K L
X W V U T SS T U V W XA B C D E FF E D C B A

(d) Alternate Vertical:

A H I P Q XD E L M T UX Q P I H AU T M L E D
B G J O R WC F K N S VW R O J G BV S N K F C
C F K N S VB G J O R WV S N K F CW R O J G B
D E L M T UA H I P Q XU T M L E DX Q P I H A