I'll add my 2 cents of answer relating to your sentence

Thanks, but I rather want them to be returned on two separate output lines, if that's possible.

As mentioned by Szabolcs functions always return a single answer. Therefore, if you want more than one answer in a single return, you need to return a single answer that can contain multiple elements, and this was already mentioned earlier, with several suggestions for different containers.

If you need to create a cell, you can print (Szabolcs already mentioned that) of your more fancy cell generation using CellPrint and related functionality. Anyway, printing or generating cells is considered as Side Effect of the function, since it is not the value returned by the function, but "something" that is done "on the side" (just compare Map to Scan to notice the difference)

I hope it helps to summarize the issue

sincerely

Szabolcs is a bona fide Mathematica expert and I am reluctant to post after him.

Nevertheless, here is a way that may help you understand how you might want to use Dynamic to achieve the display-both.

Dynamic[{data, listPlot}]
Module[{t = 1}, x0 = Table[i, {i, 1, 100}];
 y0 = Table[Sin[(20 + i)/20 t], {i, 0, 3}];
 data = N[Table[{x0[[i]], y0[[i]]}, {i, 1, 3}]];
 listPlot = ListPlot[data];
 ]

But, because x0,y0 aren't needed after the Module, they should probably be local to the Module. Try this and look at what happened to the Dynamic output above.

functionThatUsesModule[t_, length_] :=
  Module[{x0, y0}, 
  x0 = Table[i, {i, 1, length}];
  y0 = Table[Sin[(20 + i)/20 t], {i, 0, length}];
  data = N[Table[{x0[[i]], y0[[i]]}, {i, 1, length}]];
  listPlot = ListPlot[data];
  ]

functionThatUsesModule[3, 5]

calling the function again:

functionThatUsesModule[6,12]

Thanks, but I rather want them to be returned on two separate output lines, if that's possible.

Thanks! That's right. Actually there is no grey multiplication sign on my notebook, and that was my source for confusion.

Another question then arises:

Is there any way to use Module and still show the output of two different commands, as I tried to do on the original post?