Thanks for the hint that did make me look closely, and yes, I like the idea about changing the cards in the reflection! Cool. Care to explain how you did this? Were there two photos? But if so, how could you arrange the cards identically? How did you put them in this position, anyway?
I blue tacked all the cards together then blue tacked them to a small jar to keep them upright. Placed it on a glass table, with black card behind and underneath. Then used a gridspot (PM for details) on my flash gun to light it.