Dimensions: 19in/48cm tall and 13in/33cm wide. Designed for elementary school, middle school, or high school use, and also perfect for libraries, learning centers, dorm rooms, and home decor. It is printed in the USA on heavy, quality stock with bright inks that won't fade. This poster was designed by a professional team including a PhD Mathematician and a Professor of Mathematics Education. You can be confident that your poster meets the highest academic and pedagogical standards. For shipping, all Platonic Realms posters are rolled, never folded or creased, in a plastic sleeve within a sturdy cardboard tube. If for any reason your poster doesn't arrive in perfect condition, let us know and we will replace it at no cost to you. The prime-number concept is fundamental in math, and in this poster we represent—in a modern form—one of the most ancient investigations of this idea: The Sieve of Eratosthenes, which shows how a prime number can be isolated by checking whether any previous primes are a factor of it. Although the basic concept is easily grasped from the image, there are subtleties that reward a prolonged stare. You'll notice that every number is defined uniquely by its proper divisors, and that the number and type of any number's divisors are immediately apparent from the curves that intersect it. This beautiful and educational poster is ideal for the classroom, school room, club room, or dormitory.