ns on the disks (example: trial 1, 5-6 with the repetition of 'yellow
disk');  it establihed a partition between disks considered as able to go on
disks 3 and others which are not.
N.B- locations at situational level may occur between solid disks associated
to selected disks. In this case, they allow to linked selected disks through
the situational level.
N.B. first results of a qualitative study (actualy drawn with one of my
students) show that generaly situational locations on the disk or on the peg
appea