There is nothing to say about the twelve levels, so let's not say the simple ones. A little technical. I'm just saying, I'll draw a picture myself. Hey, hey, what's up?

A 6×7 grid, click on the serial number marked by my red number, and a picture can be completed in three steps at most (if you are a little deaf and can't hear the instructions of the hostess clearly, forget it).

What is the principle? People with an IQ higher than 70 can understand at a glance. Probably.