2x2 grid layout feature

[jwright8]

Thank you. When I looked again, I saw that one of my responses had a double bracket [[]], like this:
{
"type": "choice",
"choices": [["%s:Image-Box_With_X", "%s:Image-Box", "%s:Image-Box", "%s:Image-Box"]],
"target": ["%s:Image-Box_With_X"],
"layout": [2,2],
"locations": "fixed",
"instruction": ""
}

I removed the extract pair of brackets and then I received the error:
Duplicate choices are found in the choice response X_top_left!
So, it seems that we cannot have the same stimuli choice occur more than once in our responses. Is that correct? If so, that is not a big deal. I can just upload the same image but with three different names, I think.