Using this method of directional freezing (developed here on Alcademics) with thermos containers and ice ball molds to maximize the clarity of ice balls, I have been playing around with putting objects inside ice spheres.
I first did a spiralized lime that you can see here - it came out pretty awesomely.
Then the other day I made some lime wedges and lime slices and put them in my ice ball molds.
When you freeze limes, it squeezes out some of the juice so the ice ball isn't crystal-clear as it is using this method with solid objects, but it still looks great and inside a cocktail you'd probably not notice.
To keep up on my ongoing icesperiments, follow along on my Instagram page.