Im using Win10 and PsychoPy version 1.9
****What are you trying to achieve?**:MRI paradigm where each stimulus is presented for a different length of times to the one before and after in a loop.
I know how to make a block design paradigm with loops presenting stimulus given in a file. But I do not know how to vary length of each stimulus in a semi random fashion. to me it appears that duration of the stimulus in a loop is constant.
Would appreciate your help very much,