[open] Prevent a picture to be shown twice
it's me again. Hope that I'm not spaming with all my questions ;-)
I have a follow up question to my microexpression experiment. The experiment exists of 7 loops and every loop is called 7 times (see picture below for more details). In every loop there's a random picture shown (the variable 'emotion').
Here's my question: how can I prevent that one picture is shown two or more times? I need to get sure that every picture is shown only one time.