This shows a way to know if the circle/bar mean true/false, the code is that "0"= false and "1"=true, this also can be used to write binary by blinking 1or 0, this is a way to learn computers, because binary (1/0)= normal notation (true/false)=computer notation (on/off). So 1=true=on and 0=false=off.
(Btw the LED and light are another way to know if the bar/circle=on/off.)
