X-Sums / Skyscraper Killer Sudoku
Rules:
Place the numbers from 1 to 9 exactly once in every row, column, and box.
An area outlined by dashes is called a killer cage, and the numbers in a killer cage must sum to the value in the top left corner. All individual digits in a killer cage must be different. A number in a killer cage outside the grid fulfills one of two possible clue types, and if two numbers outside a row or column on the same side of the grid are in killer cages, they are of different types. The types are as follows:
X-Sums:
Call the nearest number inside the 3x3 grid sharing a row or column with the clue, X. The number in the cage is the sum of the first X cells seen when looking into the grid from the direction of the clue.
Skyscrapers:
Treat each number N as a building of height N. The number in the cage indicates the amount of buildings seen inside the 3x3 grid from from that direction, where taller buildings hide shorter buildings.