First Officer reports inability to acquire proper rest during a 30 hour lay over and calls in fatigued after the second leg of a four leg day.

Narrative

On day 2 of a 4 day trip; we ended up blocking into the gate at BOS at XA:50 local. After walking to the van for the 20 minute ride to the hotel; we arrived at the hotel at approximately XB:30. After checking in and unpacking; I finally went to sleep well after XC:00. I got up around XL:00; had breakfast and took a long walk. After eating an early dinner; I was back in my room by XT:00. I was not at all tired and tried to fall asleep by XW:00 to be ready for a XE:15 wake up call; for a XF:10 van; for a XF:45 report time in BOS. I tossed and turned all night and am unsure exactly what time I finally fell asleep. Upon reaching the airport at XF:30; I felt tired; but thought no more than a normal person would feel at XF:30. The first leg was uneventful. It was during the second leg back to BOS that I found myself yawning continuously and having trouble concentrating. I knew I was experiencing fatigue. Our pairing was supposed to continue on to ZZZZ and back to FLL with a release time of XQ:25. I knew that there was no way I would be able to last another 2 flights; so upon arrival to BOS; I informed scheduling; as per our new fatigue policy; that I was not fit to fly on to ZZZZ. I then filled out my mandatory; voluntary safety report as per Company Fatigue Policy and will inform the chief pilot within 72 hours.1. This pairing shifts sleep cycles in the worst way. I went to bed 2 hours before my alarm went off the next night. (I fell asleep after XC:00; when the next night I needed to be awake at XE:00) 2. The hotel is an excessive distance away from the airport for an after midnight arrival and XF:45 show time. 3. Both myself and the captain had rooms right next to the elevator. 4. There was street construction all night long the second night; right outside the hotel.This pairing is not safe. Please keep crew members on schedules that do not swap sleep cycles in 24 hours. In my opinion; I would rather arrive in Boston the afternoon before the XF:45 report time; that way I would have had dinner and gone right to bed.