Can i insert a clock mechanism under the fondan so the clock cake will show the real time, moving? ANyone done this? tips or ideas?

seen TV shows with alot of these things being done.. i dont think it could be hard. just make sure the clocks hands don have any abstruction. ohh and i woud enclose the clock mechanism into a plastic covering to protect both cake and mechanism. everything is doable u should show us the cake when ur done