Prompt: Prime

The Product of Two Primes

"The signal is comprised of ten groups of 69,841 bits, after which the whole signal repeats."

"66,887... that wouldn’t be...?"

"The product of two primes, yes. Exacty how we’d expect sentient creatures seeking contact to transmit graphical information."

"And?"

She indicated a folder, labelled CONFIDENTIAL.

The pictures were a grainy monochrome, but reasonably clear. The backgrounds varied – bubbling oceans, towering rock formations, forests of improbable plants, huge and bizarre cities.

The foregrounds were identical: Three unspeakably alien figures, one smaller than the others. It seemed to be the same three.

"These are...?!"

"Yes. They sent us vacation photos."