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.