What words have a horizontal line of symmetry when printed horizontally, and a vertical line of symmetry when printed vertically. The only word I have is HI.

To determine what other words have both a horizontal line of symmetry when printed horizontally and a vertical line of symmetry when printed vertically, we need to analyze the letters and their symmetrical properties.

Let's break down the word "HI" to understand its symmetry. When printed horizontally, both the letter "H" and the letter "I" exhibit a horizontal line of symmetry. This means that if you fold the word across that line, the two halves will match. Furthermore, when printed vertically, the word "HI" also possesses a vertical line of symmetry. In this case, folding the word across that line will result in a perfect match.

Now, let's consider other potential words that may have similar symmetrical properties. To keep it concise, let's focus on words that consist of two letters and are made up only of upright letters that are mirror images of each other. These letters include H, I, O, S, and X.

By examining the possible combinations and considering their horizontal and vertical symmetry, we find that the following words meet the criteria you described:

- HI: As mentioned before, "HI" has both horizontal and vertical line symmetry.
- XI: When printed horizontally, "XI" has both horizontal and vertical symmetry.
- OI: This word has a horizontal line of symmetry when printed horizontally and a vertical line of symmetry when printed vertically.

It's worth noting that there might be other combinations of letters that satisfy these criteria, but these three are the simplest and most common examples.

The word "HI" is one example of a word that has a horizontal line of symmetry when printed horizontally and a vertical line of symmetry when printed vertically. Another example is the word "MOM." In both cases, if you fold the word in half along the indicated line of symmetry, the two halves will perfectly match each other.