Digits do not repeat in any row, column, marked region or or marked diagonal. Each orange line in the grid serves three purposes: it is a palindrome (digits on it must read the same in both directions, e.g 94349); it is also a thermometer (pair) with its bulb in the centre of the line; and it is also a pair of arrows that meet in the centre with circles at the ends. The shared arrow digit is in the thermometer bulb and digits on thermometers must strictly increase from the bulb. A white dot between cells indicates that their digits are consecutive - not all dots are shown.