One of the most interesting unicorn practices have to do with sunflowers. Every generation of unicorns practices on them, and are only considered adults if they can make the flower budge.
An easy task you’d think, and you’d be mostly right. Moving the flowers themselves isn’t hard at all. However, the unicorns practicing are told to imagine that it’s the sun. The use of innate magic is tied to the caster’s specific thoughts, rather than will. So until they learn to apply their magic to just the flower, they don’t grasp how magic works, and are not counted amongst adults.