Interview questions for user interface/data visualization design?
There are a ton of lists out there of interview questions to test the candidate's programming aptitude.  But my company is very UI-focused, and everyone is expected to be able to both code and design a decent UI.  So once I've seen that the candidate can implement recursive Fibonacci and tell me its orders of growth in time and space, I want to make sure that they can design an interface that won't make the user run screaming from our app.

What questions do you ask to ascertain a candidate's interface design/data visualization skills?
Interview questions for user interface/data visualization design?
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There are a ton of lists out there of interview questions to test the candidate's programming aptitude.  But my company is very UI-focused, and everyone is expected to be able to both code and design a decent UI.  So once I've seen that the candidate can implement recursive Fibonacci and tell me its orders of growth in time and space, I want to make sure that they can design an interface that won't make the user run screaming from our app.

What questions do you ask to ascertain a candidate's interface design/data visualization skills?