Pretty Stickers Puzzle

In the scenario given, you are shown a sheet of four stickers: a purple square, a yellow square, a purple heart, and a yellow heart. The question asks which sticker is considered pretty based on the rule that a pretty sticker must have exactly one of the following traits: the color purple or the shape heart.

Let's break down the traits of each sticker:

1. Purple Square: This sticker has the color purple, but it does not have the shape of a heart, so it meets the criteria of being pretty as it has the color purple.

2. Yellow Heart: This sticker has the shape of a heart, but it does not have the color purple, so it also meets the criteria of being pretty as it has the shape of a heart.

3. Purple Heart: This sticker has both the color purple and the shape of a heart. According to the rule, a sticker must have exactly one of the traits to be considered pretty, so this sticker does not qualify as pretty.

Based on the given rule, the only sticker that is not pretty is the Yellow Square because it does not have either of the traits - purple or a heart shape. Therefore, the pretty stickers are the Purple Square and the Yellow Heart.