Let's say you have an oval shape, like a face. You draw one cartoon eye and want to duplicate it, but you want the eyes to be symmetrical on the oval - that is, the distance between the oval edge and the left eye is equal to the distance between the oval edge and right eye.
Instead of doing this by eye, how can you ensure symmetry? I was initially aligning them to center and moving each eye left/right with an equal number of spaces. But that is clearly tedious and was hoping there is a quicker way.