Since Kevin Garnett, Ray Allen and Paul Pierce joined forces, the Celtics have won 178 games, eight playoff series, two conference championships and one world title.

From the beginning, there was talk of a three-year window, and those three years represent an unqualified success. And from the start, people have been trying to figure out how they would make it work.  

It’s easy to see now how Pierce, Garnett and Allen came together and blended their talents into a coherent team, It happened so quickly in fact, that it’s easy to forget how many variables had to be overcome, worked through and sorted out.

Not just the standard issue basketball stuff like shots, minutes and the other ego trips that come part in parcel with the NBA. What sets this group apart is that they have all been willing to be a part of something larger, and that, as it often does, takes both compromise and work.

“We don’t take it for granted and I think that’s all that matters,” Ray Allen said. “You don’t just get it. It’s not given to you. We had to go out and make it happen.”

They’re still going strong three years later, through injuries, contracts and the highs of a championship and the lows of a Game 7 loss to their eternal rival. This run can’t end yet because they don’t want to leave anything on the table after spending their careers waiting for an opportunity like this.

“When we got them I don’t think anyone [knew], and we still don’t know what their expiration is,” Rivers said a few weeks ago. “It could be in a year, two years. It could be this year in the middle of it. We just don’t know the answer to that yet.”   

So, they move on with yet another cast of character. The list of supporting actors has included the likes of Eddie House, James Posey, Leon Powe, P.J. Brown, Sam Cassell, Stephon Marbury, Rasheed Wallace and Tony Allen to name the most prominent. Only three others – Rajon, Rondo, Kendrick Perkins and Glen Davis -- have remained with them from the beginning through this season.

But through it all, Allen, Pierce and Garnett have stayed relatively consistent in their performance and, most notably, in their approach with each other.

“I can say that we haven’t had too many issues that we had to deal with between the three of us,” Allen said. “Everything’s been very amicable the whole time. At worst, we’ve been amicable. At best, we’ve been as close as any other teammates I’ve ever had.”

But there were some issues last season. Not huge ones, perhaps, but small ones that gathered themselves from the dust of history and time into tangible things that had to be addressed.

“We all change,” Doc Rivers said. “We’ve all changed a little bit. Their respect for each other has grown and their respect for their other teammates, with Rondo and Perk, has grown. There’s such a trust there now.”

Rivers continued, “Where they’ve gotten better, I thought it happened toward the end of last year. The tough part about being together for too long is you start to have less patience for each other’s faults. They know what the other guy’s fault is, and when it comes out in a game they get [ticked] about it, and then they can’t play anymore. They have gotten past that part to try and cover up for each other’s faults. That’s a nice place to be, because most of the time it goes the other way.”

The success of the Celtics these last three years can be summed up in raw numbers like wins and losses, but it also holds up as a testament to what happens when people gather together in one place and make relationships work. When things do get out of whack, they have shown a remarkable ability to deal with one another.

“That’s what grown men do,” Pierce said. “We look each other in the eye and say how we feel. Doc has taught us to do that. You guys lay it out. You got something to say, then tell each other. Don’t go behind each other’s back. Solve it, end it right there, and its over with.”

Is that something he could have done 10 years ago?

“No,” Pierce said. Then he laughed. No way.  

Asked a variation on the same question, Allen offered a typically longer response. “We would have been still searching,” he said. “Trying to gain notoriety in the league, trying to gain a foothold where we were getting respect, where people know who we are, what our name is, wanting to be at All-Star weekend. Now those things are irrelevent.”

That is just one example of their differences. Pierce, ever blunt, contrasted with Allen’s more deliberate response. They got to the same conclusion in their in their own way, but they both ended up in the same place, as they often do.

“You’ve just got to respect what each other does and where you come from,” Allen said. “I might laugh at something Paul does. He might laugh at something I do. It’s not going to change me from being who I am, or doing the things that I do. We all have our perceptions and our own perspective in life.”

And yet it works.

They have all carved out their particular niche in the Celtics world. Garnett, as ever, remains the darkly foreboding storm of emotion. Pierce, straight and to the point with a captain’s responsibility to be held accountable for everything that happens around him. Allen, meanwhile, is always moving, endlessly searching for the perfect balance.

They allow each other that freedom to be what the other is not and in doing so, create this tiny oasis where all their disparate parts come together into a greater whole. And they have also learned from each other.

“I know I’ve matured,” Pierce said earlier in camp. “I’ve taken a lot of things from Ray off the court. I’ve taken a lot of things from Kevin and I’m at the point where I feel even-keeled in my life.”

Sometimes it takes a reminder, like the time Allen was in Providence and a girl stopped him on the street and told him, “I liked you better in Seattle.”

Allen considered this for a minute. “I can’t be what I used to be,” he said. “I can still be a great player, but I just have to do it in different ways.”

Their era remains open, for however long, and they know they will have to adapt to keep it moving forward. The old days, even three years ago, are a thing of the past.

But as they return to take one more shot a championship, Paul Pierce, Kevin Garnett and Ray Allen will hold true to the original vision. That’s what makes them who they are and that’s what has made them successful.