Question 6
The uppercase letters $A$, $E$, $F$, $H$, $I$, $K$, $L$, $M$, $N$, $T$, $V$, $W$, $X$, $Y$, $Z$ can be written using only straight line segments. For the $I$, one line segment is enough; for the $E$, four line segments are needed. We call a sequence of at least two of these letters a word; so it does not have to be an existing word or even pronounceable. For example, $FK$ is a word, and you write this word with six line segments.
How many words exist that can be written in uppercase letters with a total of exactly four line segments?
How many words exist that can be written in uppercase letters with a total of exactly four line segments?