The numbers outside the grid show how many buildings can be seen when looking towards the grid. So, for example, the 2 at the beginning of the fifth row means that the following combinations could be found in that row:

51874362

64873125

The small figures in the shaded rectangles show the total of the numbers in that rectangle.

*"The shaded rectangles are similar to those found in "Killer Sudoku".*

7 | |||||||||||

21 | 12 | 6 | 15 | ||||||||

15 | 3 | 10 | |||||||||

21 | 13 | 6 | 7 | ||||||||

6 | 10 | 11 | 11 | ||||||||

2 | 5 | ||||||||||

19 | 1 | ||||||||||

8 | 15 | 5 | 4 | ||||||||

10 | 12 | ||||||||||