This Latin square puzzle invites us to think of its N×N grid as a cityscape. We place the numbers 1 through N on the grid cells in the usual way — no repeats in any row or column — but we think of the numbers as measuring the heights of buildings. The clues around the edge indicate how many buildings we can see if we stand at that clue and look down the aligned row or column, with the rule being that we cannot see a shorter building behind a taller one but can always see a taller building behind a shorter one.
Select a grid cell and then type or click the digit you wish to enter. The arrow keys move your selection, Backspace or Delete erases the selected cell, and Ctrl + Z or the Undo button undoes your last entry. Press the Notes button or hold Shift while entering a digit to write it as a small mark on the cell to help you keep track of your deductions.
The Hint button will disclose just about as little information as it can to help you. Larger puzzles are harder than smaller ones; within each size there are four difficulty tiers. Starter puzzles provide you with the maximum number of clues and only require thinking one choice at a time. The remaining difficulty tiers provide you with the minimum number of clues and are differentiated by how often you are required to think ahead about the consequences of different choices to deduce the correct digit. Easy puzzles require no such thinking ahead, just spotting the right deductions one at a time. Medium puzzles require a little bit of thinking ahead, and Hard puzzles require the most.
The puzzle you see above is encoded in the address bar, so you can share a link to this particular puzzle if you like. You can also generate a printable PDF of the puzzle: