Come up with conventional signs to convey information.

Well, you can come up with many conventional signs to convey information. For example, those that inform about danger, warning or something informing signs. For example, in a store: draw a dog and cross out, this means that you cannot walk here with a dog.
In the forest: for example, draw a match, all sorts of fireworks and also cross out, of course, as you understand, this means that you cannot launch fireworks here and use and neglect a match. Draw a branch and a hand that reaches for a branch. That is, you cannot break branches.
Draw a trash can and the inscription “do not litter”.
And so on.