A Poster About Prime Numbers We're going to design a poster about prime numbers, which will appear in a mathematics magazine for middle school students. 
The poster should be both visually attractive and mathematically rich.
Do you have any suggestion for the content or idea of the poster?
Thanks.
Update: Finally! Thanks to the ideas offered here, a poster (based on the sieve of Eratosthenes) was designed and printed as the cover of our magazine. The numbers below the sieve are $4, 6, 8, 9, 10, 12$. The numbers inside the sieve are $ 2, 3, 5, 7, 11$. The number above the sieve is $1$.


I think something that shows what makes a number not prime would be interesting. You could have a list of numbers (2, 3, 4, etc) filling the poster. Primes would be a particular colour, say white. Each prime would have a border around it with a unique colour, such as blue for 2, yellow for 3, etc.
A number that isn't prime would be coloured with the border colours of the primes that compose it. In this example the number 8 would be blue. If a number has two or more prime factors it could be partially each colour. In this example 6 would be half blue and half yellow.
You could also colour the composite numbers as a combination of its factors, making 6 green. But that'd probably be less intuitive and might end up with some weird shade of brown down the line.
