If the letters of the alphabet were put in rows of three then each set of words can be made from only the letters in a given column.
A B C
D E F
G H I
J K L
M N O
P Q R
S T U
V W X
Y Z
Trying the same thing with two columns is a problem since all of the vowels A, E, I, O and U, and even the occasional vowels Y and W will all appear in the left hand column, and the right hand column would be reduced to onomatopoeic non-words like BZZZ and PFFT.