Hi,

I'm building a Stroop script in which blocks present 40 trials (20 food-related, 20 neutral) containing 4 colours (red, blue, orange, green) in a semi-random fashion. Specifically, no more than 2 words from the same category (food/neutral) and no more than 2 words of the same colour can appear consecutively. Each item (20 food, 20 neutral) is presented once and colours are evenly distributed. 

I wanted to ask about how to accomplish the semi-randomisation efficiently and ensure the colours are evenly distributed. Parts of my script are below:


********** Food *********

<item Food>
/ 1 = "Cake"
/ 2 = "Cheese"
/ 3 = "Potato chips"
/ 4 = "Pasta"
/ 5 = "Bonbon"
/ 6 = "Salad"
/ 7 = "Meatball"
/ 8 = "Cookie"
/ 9 = "Ice cream"
/ 10 = "Kebab"
/ 11 = "Bun"
/ 12 = "Yoghurt"
/ 13 = "Whipped cream"
/ 14 = "Chocolate"
/ 15 = "Hamburger"
/ 16 = "Meat"
/ 17 = "Peanut butter"
/ 18 = "Croissant"
/ 19 = "Vanilla custard"
/ 20 = "Treacle waffle"
</item>


<list Food_Items>
/ poolsize = 20
</list>


<text Food_Red>
/ items = Food
/ color = (red)
/ fontstyle = ("Arial", 80pt, true)
/ select = list.Food_Items.nextindex
</text>

<text Food_Blue>
/ items = Food
/ color = (blue)
/ fontstyle = ("Arial", 80pt, true)
/ select = list.Food_Items.nextindex
</text>

<text Food_Orange>
/ items = Food
/ color = (orange)
/ fontstyle = ("Arial", 80pt, true)
/ select = list.Food_Items.nextindex
</text>

<text Food_Green>
/ items = Food
/ color = (green)
/ fontstyle = ("Arial", 80pt, true)
/ select = list.Food_Items.nextindex
</text>



**** Neutral ****

<item Neutral>
/ 1 = "Tape"
/ 2 = "Paperclip"
/ 3 = "Cupboard"
/ 4 = "Felt-tip"
/ 5 = "Mobile phone"
/ 6 = "Ball pen"
/ 7 = "Scissors"
/ 8 = "Diary"
/ 9 = "File"
/ 10 = "Pushpin"
/ 11 = "Printer"
/ 12 = "Monitor"
/ 13 = "Cable"
/ 14 = "Notice board"
/ 15 = "Bookshelf"
/ 16 = "Envelope"
/ 17 = "Stamp"
/ 18 = "Wastepaper bin"
/ 19 = "Punch"
/ 20 = "Stapler"
</item>


<list Neutral_Items>
/ poolsize = 20
</list>


<text Neutral_Red>
/ items = Neutral
/ color = (red)
/ fontstyle = ("Arial", 80pt, true)
/ select = list.Neutral_Items.nextindex
</text>

<text Neutral_Blue>
/ items = Neutral
/ color = (blue)
/ fontstyle = ("Arial", 80pt, true)
/ select = list.Neutral_Items.nextindex
</text>

<text Neutral_Orange>
/ items = Neutral
/ color = (orange)
/ fontstyle = ("Arial", 80pt, true)
/ select = list.Neutral_Items.nextindex
</text>

<text Neutral_Green>
/ items = Neutral
/ color = (green)
/ fontstyle = ("Arial", 80pt, true)
/ select = list.Neutral_Items.nextindex
</text>

**************************** TRIALS *****************************

****** Food Trials *******

<trial Food_RED>
/ stimulustimes = [0 = Food_Red]
/ responsetime = 0
/ correctresponse = ("A")
/ validresponse = ("S", "K", "L")
/ trialduration = 2000
/ posttrialpause = 1000
/ responseinterrupt = immediate
</trial>

<trial Food_BLUE>
/ stimulustimes = [0 = Food_Blue]
/ responsetime = 0
/ correctresponse = ("S")
/ validresponse = ("A", "K", "L")
/ trialduration = 2000
/ posttrialpause = 1000
/ responseinterrupt = immediate
</trial>

<trial Food_ORANGE>
/ stimulustimes = [0 = Food_Orange]
/ responsetime = 0
/ correctresponse = ("K")
/ validresponse = ("A", "S", "L")
/ trialduration = 2000
/ posttrialpause = 1000
/ responseinterrupt = immediate
</trial>

<trial Food_GREEN>
/ stimulustimes = [0 = Food_Green]
/ responsetime = 0
/ correctresponse = ("L")
/ validresponse = ("A", "S", "K")
/ trialduration = 2000
/ posttrialpause = 1000
/ responseinterrupt = immediate
</trial>



****** Neutral Trials *******

<trial Neutral_RED>
/ stimulustimes = [0 = Neutral_Red]
/ responsetime = 0
/ correctresponse = ("A")
/ validresponse = ("S", "K", "L")
/ trialduration = 2000
/ posttrialpause = 1000
/ responseinterrupt = immediate
</trial>

<trial Neutral_BLUE>
/ stimulustimes = [0 = Neutral_Blue]
/ responsetime = 0
/ correctresponse = ("S")
/ validresponse = ("A", "K", "L")
/ trialduration = 2000
/ posttrialpause = 1000
/ responseinterrupt = immediate
</trial>

<trial Neutral_ORANGE>
/ stimulustimes = [0 = Neutral_Orange]
/ responsetime = 0
/ correctresponse = ("K")
/ validresponse = ("A", "S", "L")
/ trialduration = 2000
/ posttrialpause = 1000
/ responseinterrupt = immediate
</trial>

<trial Neutral_GREEN>
/ stimulustimes = [0 = Neutral_Green]
/ responsetime = 0
/ correctresponse = ("L")
/ validresponse = ("A", "S", "K")
/ trialduration = 2000
/ posttrialpause = 1000
/ responseinterrupt = immediate
</trial>


<block 1>
/ preinstructions = (Instructions)
/ trials = [1-40 = noreplacenorepeat(Food_RED, Food_BLUE, Food_ORANGE, Food_GREEN, Neutral_RED, Neutral_BLUE, Neutral_ORANGE, Neutral_GREEN)]
/ postinstructions = (Block1_End)
</block>


*************

Thanks!

Jay