Randomization with restrictions

[E.Hartstra at inter.nl.net]

Dear fellow E-Primers,

Currently I’m working on a picture naming experiment. In total there will
be 40 pictures shown to the participants and each picture is shown two
times. Pictures will be presented with either a red or bleu border. This
colored border informs the participants in what language they have to name
the picture.
Pictures are chosen randomly with the restriction that no identical
picture is presented in occurrence of each other. I’ve done this with an
Inline script. Now comes the tricky part and I really hope someone has an
idea how to do this.
The idea is that after every 2 trials the border changes from color,
indicating that the pictures have to be named in another language. This is
done after each 2 trials. At this point I am lost how do to this via the
script. I had the idea that if I make a SlideObject with two slides, one
with a red border and another with a bleu border, I could program e-prime
in such a way that it will switch between the slides every 2 trials.

I hope it’s clear what a mean and I’m looking forward to the replies.

With kind regards,

Egbert Hartstra