Rub el Hizb is a symbol or pattern that Muslims use in their religious books and decorations. It looks like a square or rectangle with four sections, each containing some words from the Quran (which is the holy book of Islam). The symbol is often used to break up long texts and make them easier to read, or to mark important sections of a book. It's kind of like how in English we use paragraphs to break up a big chunk of text into smaller, easier-to-read sections. Rub el Hizb is an important symbol for Muslims because it reminds them of the Quran and helps them focus on their faith.