Arabic Sudoku Puzzle

Here's Sudoku with real Arabic numbers, as opposed to the phony Western version of Arabic numerals that we're most familiar with. Though the arabs are widely credited with inventing the number zero, that honour really belongs to the Hindus. The decimal place value system dates back to the Brahmis (who used a space for a zero). The Arabs traded widely and brought zero back from India, which must have been disappointing for their families, however much they tried explaining it.

Anyway, back to the puzzle, place the numbers 1-9 in the grid so that every row, every column, and each of the nine 3x3 square contains only one occurrence of all the numbers from one to nine.

You should be able to solve any puzzle here without writing anything down, and they all have only one solution. If you feel you can't go, you can click the 'give me a hint' button, and any errors you have made will be highlighted in red, or if you've made no mistakes, a green square will show where you can go next. If you try to place a number where it already exists on that row, column, or small square, both occurrences will be highlighted in red.