I added a red blinkie to my left front fork last night.
This only works on BMX and Mountain bikes that have a round fork tube.
The Blinkie is aimed slightly to the left.
It does get "eclipsed" by my left foot every time I push the left pedal.
I put it there mainly to avoid getting "right hooked".
I have another red blinkie on the seat-post and a green blinkie facing forward, on the handlebars.
I keep them on steady mode.