I may deal with the playing cards but I am still curious how to put the wood board into the bottle. :-O
Probably not how it was done, but is it possible to craft a bottle in such a way that the refraction index makes the content appear larger than it actually is?
There is a trick where you can wet wood for a very long time and it becomes more malleable. This lets you do things like, place a solid metal beating within a single hunk of wood.