The triangle is gone, but the Knicks still can’t seem to grasp Jeff Hornacek’s high-tempo offense. And that’s an awful sign for a Knicks coach hired by ousted Phil Jackson.

Hornacek has blamed a short preseason for players not knowing the plays perfectly. He cracked before the season opener he wished he had “11 preseason games” this October with a young, Carmelo Anthony-free roster.

That 0-5 preseason has been followed by an 0-3 start, and the grumbles are growing louder in the Knicks locker room over the poor grasp of the playbook. Who knew the Knicks defense would be better than the offense?

Veteran Courtney Lee charged the Knicks aren’t giving full attention at practice. The Knicks scored 33 first-half points in the Boston debacle Tuesday and finished the game shooting 1-of-12 from the 3-point stripe.

“We messed up on a lot of plays, whether it was the ball getting delivered on time, or one or two guys not being on the same page as far as play calling,” Lee said. “That’s on us, we got to pay attention more in practice and make sure we execute when we’re out there.”

Lee said the offensive chaos is also hurting the club’s transition defense. The Celtics got out on the break to punish the Knicks in the 110-89 fiasco at TD Garden.

“If you are out of position, where you’re supposed to be here, it makes it hard for our defense to get back and get set,’’ Lee said.

Before the OKC season opener, Hornacek was asked directly if the players knew the plays.

“We’re still having to go over it,’’ Hornacek said. “Most guys have most of the plays. Every once in a while, it’s, ‘What is that?’ It’s a process.”

A process to flourish without Anthony’s automatic offense.

“We’re going with new offensive stuff,’’ Hornacek said. “And we could always [last year] just say to Carmelo, OK here’s the ball, go score. We have to do it more as team.”

The Knicks face a must-win Friday against the Nets at the Garden. If they can’t beat their lowly neighbors, there’s a shot Hornacek’s club gets off to an 0-7 start. Cleveland, Denver and Houston are on tap after Brooklyn.

“In my mind, we’re going to win games,’’ said Kristaps Porzingis, who had a brutal night in Boston. “There’s no doubt we might [not] never win a game.’’

Maybe the offense becomes more organized once French rookie point guard Frank Ntilikina is healthy. He’s missed two of the three games with a sprained ankle but is expected to practice Thursday.

Hornacek has more new stuff to teach but is waiting for the Knicks to master what’s been laid out.

“We didn’t push the ball,’’ Hornacek said in Boston. “When we did get a rebound or stop, we went three-quarters speed up the court. We got to fly it up the court so we can get some easy kickouts.’’

The Knicks also are missing open looks from the 3-point line, shooting 24 percent. Tim Hardaway Jr. is off to a horrific start in his second Knicks stint, shooting an unsightly 24.2 percent as the club’s second option. Though he’s bothered by an ankle tweak, he, too, pointed out the offense has guys “just running like we don’t know what’s going on.’’

“I thought we hung our heads a bit and kind of felt sorry a little bit when they weren’t making the shots,” Hornacek said.

Hardaway, who shot well in the preseason, owned up to his atrocious first three games after signing on for four years and $71 million.

“When the ball’s in my mind and I feel like I have daylight, I feel like it’s leaving my hand really good, just like it did in preseason,’’ Hardaway said. “It’s just either too long or too short, but they’re all on line. And some rattle in, some rattle out. But I’m not going to stop shooting. That’s what I’m here for.”