Season 5 E22 at 12:26 Wesley was writing on the white board the riddle. Then at 12:28 his writing font completely change. It that changes font again at 12:28 and 13:08.
Wesley says something is a "semordnilap" which means a word, phrase, or sentence that can be read backwards but then he also called it a palindrome, which it isn't. Palindromes backwards may be semordnilap but a palindrome is a word, phrase, or even numbers read the same either way like "racecar" or "Madam I'm Adam".