The boulder shaped like a triangle from the left view point in the small depression about 100 yards past the main cluster of boulders if your coming from Mountain trail. My friend Rob and I got the arete from the sit up the triangle, the roof on the back side, and the crimpy face between the two routes (Not claiming FA just info). Great boulder. Around the other side of the boulder on the boulder leaning against it, there is a steep crumbly section that has a good line going from the bottom left up and right.
Go past the main cluster and down the hill slightly towards south mountain
Mountain Project's determination of some of the classic, most popular, highest rated routes for Bermuda Triangle Boulder:
By M Sprague Administrator From: New England Apr 24, 2011
Ward Smith did the straight up arete on the left side of the main face (no name that I know of so we imaginateively called it Ward's Arete). The other lines that you did may very well be FA's, so go ahead and give them names etc., and any other lines / boulders you can come up with names for. We can always correct them later if need be. Dave Quinn or I did the overhanging orange face on the boulder in back. It needs a name though.
The arete , I think, was Ward's first route in the area. There is a funny story around it. Ward, and maybe Chris end Ed Esmond had rediscovered the place, but Ward was keeping it's location secret from me, afraid that I would let the cat out of the bag. A little pissed off, I said to myself "Some friend you are! I'm going to find them my self, you F'er". Not really knowing Pawtuckaway, I looked at a map trying to figure where boulders might be, then used my intuition. I didn't even know what entrence he had used. Anyway, somehow I picked the right entrence and ended up parking in the exact right spot, first time. I then hiked in some and sat down on my pad in the sun and meditated. When I got up it was like I could feel exactly where they were and I went directly to the boulders. When I saw the arete I knew I was at the right spot because I recognized his workmanship cleaning the boulder and reinforcing a handhold, later confirmed. It was a really cool experience.