Think of “your terminal” as an output file, which in fact it is.   Three processes, all running independently of one another, are simultaneously writing lines of text to that file.   In what order, therefore, will the lines of text appear?   God only knows.

It would get even more tricky if the character-strings that each process was writing did not end in a newline character.   As it happens, most programming languages buffer character-output such that they only write complete text-lines at a time.   In the worst case, the characters being output by the various competitors could be intermingled.