Stimulus identity in a factorial design is not updated

[NicoletaPrutean]

Hello everyone,

I would like to know how to change on each block the stimulus identity tied to each condition of a factorial design.

In the example below I want to use all 8 stimuli (defined in stim_row) across 2 blocks (1 block = 4 trials = 1 design repetition).
But I see the 4 stimuli from block 1 also in block 2. How can I avoid this?

Thank you.

  blocks = 2
  stim_row = [stim1,stim2,stim3,stim4, stim5, stim6, stim7, stim8]
  stim_idx = 0

for (var j = 1; j<=blocks; j++ ){  
  for (var i = 0; i < design.length; i++) {
      if (design.condition1 == "this" && design.condition2 == "this"){
        design.stimulus = stim_row[stim_idx]
        stim_idx = stim_idx + 1
      } else if (design.condition1 == "this" && design.condition2 == "that") {
        design.stimulus = stim_row[stim_idx]
        stim_idx = stim_idx + 1
      } else if (design.condition1 == "that" && design.condition2 == "this") {
        design.stimulus = stim_row[stim_idx]
        stim_idx = stim_idx + 1
      } else if (design.condition1 == "that" && design.condition2 == "that") {
        design.stimulus = stim_row[stim_idx]
        stim_idx = stim_idx + 1
      }
   }
}