When something is said to 'come full circle' it refers to ending in a position which is similar to or the same as a previous one or a complete reversal of an original position. This expression is usually used to say that nothing substantial has changed since you started. Similar in meaning to 'be back where we started'.

1. Flat caps and brogues are very popular these days. It seems that fashion has come full circle.
2. After all the extra tuition and classes, I still failed the exam. I have come full circle and am no better off.

1. The design of the product has come full circle. Even after trying out a lot of different options, we've ended up going for the original design.
2. I was in accounting at the start of my career before I left to become a teacher. Now I've returned to accounting again, so my career has come full circle.