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Randomized stimuli in sequential block order

Hi PsychPy Team,

I need your help when designing a builder-based offline experiment. We are working with Windows 10 and PsychoPy Version 2020.2.10. We want to conduct an experiment where participants are shown 20 videos in total. The experiment should consist of 4 blocks, each presenting 5 random videos out of the list of 20 videos. The assigning of the 5 videos to the blocks need to be randomised, meaning that each participant has 5 different videos in a randomized order in each of the blocks. The order of the blocks need to be sequential. We are struggling on how to combine those things. We have tried to work with 2 loops: one sequential for the order of blocks and one for the randomization of the videos within each block. Unfortunately, up to now, if we do it like this, all 20 videos are shown in each block.

Does anyone have an idea on how to only select 5 videos for each block but ensuring that those 5 videos vary between participants?

Any help is much appreciated!
Take care,



My independent randomisation demo might help here.

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sorry for the late response but thank you again for your help :slight_smile: it is much appreciated!