I like the last one! Sort of obvious

What about the ones that WE all use?

Your signal is on, or someone flashing their brights at you, those sort of signals??

Do you give 3 fingers down for a trike?

What if the rider flashes you? Is that a signal?

Actually, there are even more intricacies that some use. The V salute ("peace sign" is actually for V-Twin riders (e.g., Harley Touring) vs. closed 2 fingers for Boxer engines (e.g., BMW RT types.)Four closed fingers are used for the in-line 4-cylinder sport bikes (e.g., Honda CBR100RR) and - if you're up to it - you can do a V-4 salute4 too!

I shouldn't reveal this to the world yet, but there is a "new wave" so to speak. It is performed with the (helmeted) rider's left hand lifted from the grip, moved outward to the end of said grip and tightly balled into a (gloved) fist. This is the "hammer". It is reserved for sport riders and acknowledges their common addiction to high horsepower. Apparently this started on the canyon road around Tortilla Flat, Arizona and spread west...