For some reason the desmos engine doesn't do mod(x,3)=0, perhaps it's graphing an infinately small point. If you allow the value of the modular function to be less than a small number, say, mod(x,3)<0.01, then you will see the points you expect.
Verbatim is defined as an exact repetition without changing the words. An example of verbatim is when you quote someone exactly without changing anything. word for word; in exactly the same words. Origin of verbatim.
adj. 1  in exactly the same words; word for word:to repeat something verbatim. 2  corresponding word for word to the original source or text:a verbatim record of the proceedings. 3  skilled at recording or noting down speeches, proceedings, etc., with word-for-word accuracy:a verbatim stenographer. corresponding word for word to the original source or text:a verbatim record of the proceedings. 2  skilled at recording or noting down speeches, proceedings, etc., with word-for-word accuracy:a verbatim stenographer.