Randomize the order of the list of questions (Question Block Rotation).

Q1 - Common Question 1
Q2 - Common Question 2

Q3 - Block 1 Question 1 
Q4 - Block 1 Question 2
Q5 - Block 1 Question 3

Q6 - Block 2 Question 1
Q7 - Block 2 Question 2
Q8 - Block 2 Question 3
Q9 - Block 2 Question 4

Q10 - Block 3 Question 1
Q11 - Block 3 Question 2

Q12 - Common Question 3
Q13 - Common Question 4

Set up all the questions in the survey. This will be the basic frame of the Survey

Add the Advanced Randomizer quesiton after Q2, i.e. Just before the first block question

Identify the first question of each block that is to be randomized and add these questions to the randomizer. In this case the questions are Q3, Q6 and Q10

In the Randomizer settings select the "Randomize The Order of the list of questions (Question Block Rotation)" option

Identify the Block Termination question which in this case is Q12. Set this question as the Block Termination question

Save the settings and click on the Done button to save the Randomizer

To complete the process setup branching for each of the last question in the Block to the Block termination question. So here the last question of each block is Q5, Q9 and Q11. Set up branching for each of these quesitons to Q12 which is the Block termination question.

Setup all the quesitons in the Survey

Add the Advanced Randomizer question just before the first question of the block. Click on the Add New question link to add the Randomizer from under Advanced Questions

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Add the first question of each block to be randomized to the Randomizer. In the above case it is Q3, Q6 and Q10

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Select the "Randomize The Order of the list of questions (Question Block Rotation)" option

Select the Block Termination question which is Q12 in this case and save the settings

Click on the done button to save the Randomizer

Now setup branching for the last question of each block to the Block termination question. In the above case set up the default branching for Q5, Q9 and Q11 to the Block Termination question Q12

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Can I set up Randomization within Randomization?

No. Currently Randomization within Randomization is not possible. You can have multiple Randomizers in the survey however, they shouldn't overlap.