Engineer and Youtuber Mark Rober had the idea of producing a 'friendly' horn for those times when a full horn blare is not needed, and even a quick tap of the horn pad feels inappropriate.
The three horns are unique, with the first being two higher-pitched tones close together. This could be used to kindly move a driver along, taking their time at an intersection.
The second is by far the cutest, producing a chirping sound - not unlike a phone message notification. This could be used for thanking someone or the "nice car, bro" signal.
Finally, the third is kept for circumstances that really piss you off. The train horn would definitely gain the attention of not only the target, but also the whole neighbourhood.
Rober did this on the cheap, purchasing parts that could easily be found in hardware or technology shops.
A soundboard, amp, PA speakers, an in-line inverter and small horn buttons were just some of the parts he used. The buttons even light up at night.
With the help of a fellow Youtuber, and a lot of drilling, the three horn buttons were permanently fixed to the centre console of his Volkswagen Jetta.
The full explanation of how he put it together features in the above video.
As cool as it is, we highly recommend gaining advice on regulations before attempting this!