No school these days because of COVID-19 here in Germany. School material and homework are send by email. I am teaching my daughter now. Two weeks before easter holidays she got the additional homework to do a research paper about the eye. One of the given topics was the visually impaired and how they find their way in everyday life. I didn't notice braille before, but now my daughter and I see it everywhere, especially on medical packaging, and we're trying to read it sometimes. Then, out of the sudden, my daughter asked me if blind people also have wristwatches and what they would look like. A few days later the idea for quattro was born...
Press the upper and lower button simultaneously.
Press one of the four buttons to read the according digit. Upper button hh:mm, right button hh:mm, lower button hh:mm, left button hh:mm.
Touch the four round recesses to read the according digit.