Millisecond Forums

> 1. can i set 6 stimuli (pictures) from 3 different files to be displayed in a circle (like a clock)?

Yes. Define the positions in e.g. a <list>, assign them to the respective <picture> elements as needed.

> 2. can i set that only 1 pictures to change randomly with a picture from a specified file to create the flicker effect?

Yes. It's unclear to me what the specific problem here is, so I'm not sure what else to say. Perhaps you can elaborate.

1. i„m having trouble with the specific positions so that i can create a circle (so far all i could do was a square). 

2. 6 pictures will be display for 250 ms, than a blank image for another 250 ms, and then i need to display 6 pictures again (5 of them have to be from the initial display and in the exact same position and 1 has to be different, randomly selected from one specific file), than the blank image and then again the initial 6 pictures, and so on, until the participant give an answer. 

In general, I'd recommend taking a look at the available flicker paradigm script:

https://www.millisecond.com/download/library/FlickerParadigm/

Re. #1: I'm having trouble understanding the profound difference between arranging objects in a square and arranging them in a circle. Obviously, 6 objects do not make up a circle in and of themselves. So, what "positions" on the hypothetical circle do you want the objects to inhabit? 12 'o clock, 3 'o clock, etc.. Do you want six *fixed* positions around the hypothetical circle or a larger set and just pick six per trial, etc.?

FWIW, Inquisit has trigonometric functions and you can use those to compute exact positions around a circle. See e.g. the SDRT ( https://www.millisecond.com/download/library/SpatialDelayedResponseTask/ ) for an example of that.