Shuffling a list with a constraint

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Published on 2011-11-19T17:45:23Z Indexed on 2011/11/19 17:51 UTC
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mathematica

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conditional

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random-sample

Preparing a new psychophysic experiment, I have 48 original stimuli displayed 4 times (4 conditions). Resulting in 192 trials. Trying to randomize the order of presentation during the experiment, I need to maximize the distance between the 4 display of the same original stimuli.

Please Consider :

Table[{j, i}, {j, Range[48]}, {i, Range[4]}]

Where j is the original stimuli number and i the condition

Output Sample :

 {{1, 1}, {1, 2}, {1, 3}, {1, 4}, 
  {2, 1}, {2, 2}, {2, 3}, {2, 4},   
  ...
  {47, 1}, {47, 2}, {47, 3},{47, 4}, 
  {48, 1}, {48, 2}, {48, 3}, {48, 4}}

How could I shuffle the order of presentation of those 192 items, maximizing the distance between identical item with regard to j the original stimuli number ?

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