Can anyone have a code about presenting four pictures at the same time? I need to control the position of four picture stimulus through codes. What i want to present is in this photo.
Are you trying to do this in Coder without using Builder components?
No, I focus on builder components. I just want to use coder to control the position of stimulus.
Hello,
you could code the positions of your stimuli in an Excel-file, xpos1, xpos2, ypos1, ypos2 and refer to these variables in position-property of the respective picture-component. Do not forget to set the Position to update for reach trial → change constant to set every repeat.
Alternatively, you could use some code. Insert a code-component before your picture-component. In the Begin Experiment tab, insert the following code:
xpos = [-.2,.2]
ypos = [-.2,.2]
Notice, I am using height as screen unit. If you use a different screen unit, you need to adjust the xpos/ypos-values accordingly.
In the Begin routine tab, add the following code:
shuffle(xpos)
shuffle(ypos)
In your first picture-component enter (xpos[0],ypos[0]) as position and set it to update. In the second picture-component enter (xpos[1],ypos[0]), in the third (xpos[0],ypos[1]) and finally the fourth picture-component add (xpos[0],ypos[0]). Don’t forget to set all Position-properties to update.
A good source is the book Building Experiments in PsychoPy by Jonathan Pierce and Michael MacAskill (2018). 
Best wishes
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It’s nice of you! 
Your answer is so detailed! Now I’ve learnt two methods to control the position of more than one picture stimulus. 
Thanks sincerely!
Best Wishes!