Descriptive Pairs Tile Sudoku

For once, the title is, well, descriptive. Every cell in the grid below contains a number between 1 to 9, inclusive. All numbers in the same row, or column, or bold outlined box are different. There are 16 rows, 16 columns and 9 boxes. Clues outside the grid take the form of a pair of numbers. For numbers i,j this means at least one of:
  • the ith cell contains value j or
  • the jth cell contains value i.
I discovered Tile Sudoku, and this particular layout, on Grandmaster Puzzles. I first spotted the descriptive pairs variation on Prasanna Seshadri's blog.
Desciptive Pairs Tile Sudoku