I Don’t Understand The Picture

Normally graphics are meant to be nice and simple to allow easy interpretation. It should be clear what the sign means from the picture and the words should just be an extra. For many years I thought the “stone chip” road sign was actually a hammer hitting the road and making chips of stone fly around. It took me years to see half a car there.

UK traffic sign 7009.svg
By UK Government OGL v1.0, Link

I was filling the car up with petrol at my new favourite local petrol station and I spotted the warning sign.

Warning Sign At Petrol Station
Warning Sign At Petrol Station

Most of these signs seem to make sense to me but I’m really struggling to see what the “stop motor” picture is. I can see a key and then a face mask?? I honestly have no idea and I’m glad there was English written on the warning because I wouldn’t have figured it out. Not that I leave the engine running when I fill up with petrol but, you know.