What was Big Willy Shakes going for?
On the one hand, this phrase is straightforward. It means something has come back to where it started, making a full circle. On the other hand, there's more than meets the eye when it comes to this saying.
Edmund references an old concept about Fate and Fortuna. Greek mythology says that the goddess Fortuna would spin the wheel of fortune (nope, not the game show) and see where it lands. That would decide people's fate.
So while Edmund is using a metaphor about coming back to the starting point, he's also drawing on the idea of a literal wheel that was spun by Fortuna. It's a metaphor, but it really happened.
And he's right. In the beginning of the play, he's the son nobody wants and it kills him. He gets mad at Edgar because their dad, Gloucester loves Edgar and not him. Can you blame him? So he plots against his bro and then gets here, right back where he started. His aggression towards his brother prompts Edgar to fight against Edmund. So, he's killed by his own brother for starting a war against him.
Now that's not a circle we wanted to see completed anytime soon.