Skyscrapers

Medium Skyscrapers uses a 6×6 grid with sparser clues than easy — a clear step up. Thirty-six cells with six possible heights each, and several border positions left blank, so you have to extract more from every clue that is shown.

Cross-referencing opposite clues becomes the main technique. When you know both the left and right clue for a row (or the top and bottom for a column), you can pin down where height 6 goes. If left=2 and right=1, the 6 must be last; if both clues are 2, the 6 is somewhere in the middle. Enumerate the arrangements a clue allows for a line and keep only the ones that fit — combined with Latin-square elimination, this drives the solve.

Use pencil marks to track which heights remain possible in each cell; a 6×6 grid is enough that holding it all in your head gets unreliable. When a cell drops to a single candidate, place it and watch the cascade through crossing lines. Every board is uniquely solvable with no guessing. Ready for a bigger grid? Try hard (7×7).