4 blocks, each:
  14 foundations to make flat slope on top of the 14 slopes
   8 foundations to make a slope inclined

4 blocks, each:
  4 halftile slopes

1st block: no neighbouring foundation in the north, so walls on the north border
2nd block: neighbouring foundation in NW, only wall in NE
3rd block: neighbouring foundation in NE, only wall in NW
4th block: neighbouring foundation in NW and NE, no walls on north border