Luck & Vogel (1997)-like task?

[Alex Francis]

Greetings,
I need to present a task similar to one used by Luck & Vogel (1997, 
"The capacity of visual working memory for features and 
conjunctions", Nature 390) in which, on each trial, 8 distinct 
(non-overlapping) color patches are presented at random locations on 
the screen.

I can come up with a brute-force way to do this in eprime, 
randomizing X- and Y-axis frame location values, but the amount of 
randomization, comparison and re-randomization seems prohibitive for 
8 squares (and there is an obvious possibility of getting stuck in an 
infinite loop).

Does anyone out there either have such a script I could copy that 
already does this, or a suggestion of a more elegant and foolproof 
way to place objects randomly on the screen without having any of them overlap?

Thanks in advance,

-alex


   Alexander L. Francis         http://web.ics.purdue.edu/~francisa
   Assistant Professor                          francisA at purdue.edu
   Speech, Language & Hearing Sciences       ofc. +1 (765) 494-3815
   Purdue University                         lab. +1 (765) 494-7553
   500 Oval Drive                            fax. +1 (765) 494-0771
   West Lafayette IN 47907-2038
   USA