Twenty one

When going to 11 isn't enough...

Every row, column and outlined region contains all numbers from 1 to 8, one per cell. All adjacent cells which differ by 5 are marked by a dot on their common border. Symbols outside the grid indicate a property shared by the first two cells in that direction. Same symbols mean same property, different symbols mean different property. Possible properties are:
  • Big: number is 5,6,7 or 8.
  • Small: number is 1,2,3 or 4
  • Odd: number is 1,3,5 or 7
  • Even: number is 2,4,6 or 8