Dimwit #1: Ah, use a 555 timer.
Dimwit #2: Use an Arduino with the Blink sketch.
Senior Software Developer: I'll use a Linux board with a blink program running on Node.js. The blink program will watch for the alarm condition and blink the LED in response. The program will also provide a web based configuration interface. What if marketing changes the requirements from a simple blink pattern to:
blink blink (pause) blink blink (pause) etc...
The simple 555 timer approach would be too inflexible.
The arduino approach would require altering, recompiling and re-flashing the firmware.
The senior software developer approach would be sufficiently flexible that you could connect a web browser and reconfigure the blink pattern.
Each blink pattern can be given a name and saved. Such as the slow-blink, fast-blink, double-blink, etc. Each pattern consists of a list of on/off states associated with a duration in milliseconds. Anyone can point their browser to this and reconfigure new blink patterns that become popular.
What could possibly go wrong?