Just a simple font that's made to look like klaxons, blinkers, sirens, warning flashers, etc. I made this design small so that the klaxons could be placed onto other pixel art.
Perhaps I'll do a bigger version of this which animates like a rotating police siren! That would likely take 8 frames or more for each glyph, so it would be fairly arduous.
Original size: 10.5pt (use multiples of this value for pixel perfection)