First note that the bold words are a little odd, and some of them unusually long. There are exactly two of each length from 5 to 16 characters, and if you compare them letter-by-letter, you will see each same-length pair has one position where both words have the same letter, such as S at the end of AGNES and NAILS. If you collect all these letters, they spell SEE WALLY WOOD. It you research Wally Wood, a comic book artist, you will find his “22 Panels that Always Work.” Each of the 7 panels in this puzzle is an example of one of the 22 types, such as “silhouette,” “one big object,” etc. If you assign letters A–V to the 22 panels in the order they appear, and then collect the letters for the 7 types of panels represented in the puzzle, they spell SHADING.