Logic Masters Deutschland e.V.

Normal 4x4 Sudoku: Place the digits 1-4 exactly once in every row, column, and 2x2 box.

Skyscrapers: Digits in the grid represent skyscrapers, with their values corresponding to their heights. Taller skyscrapers obscure all shorter skyscrapers behind them. Clues outside the grid indicate the number of skyscrapers that can be seen in that row/column, from the line of sight of the clue.

Clones: Gray cells contain exactly the same digit.

*** Solution checker includes the gray cells outside the grid.

Solve online at this SudokuPad link.

Check my other puzzles here.