Rules: Fill the grid with digits from 1 to n (1-6 for the example) so that no digit is repeated within a row/column. Numbers in the grid indicate the difference between the biggest and smallest digit in the visible cells. A digit can see others until its view is blocked with a triangled cell. If there is only one cell in sight, the number indicates the digit itself.
Background: This is one of my inventions. I made for the first time in OAPC 4. Also it appeared in Finals of 18th WPC.