When your spiffy Computerized, Programmatic Sudoku Puzzle Generator is not available, consider the low-technology, self-involving, self-sufficient random number generator and cell locator tools. You need at least 17 starting numbers and symmetry is required only for the obsessive compulsive (or Virgo people). Don’t start with too many numbers, though, unless creating unsolvable puzzles is your goal.
There’s an impressive video animation of a Sudoku puzzle (3 MB, 2:26) along with a soundtrack for which I could only hear the first two notes.
It starts and solves a puzzle step by step on Mark Huckvale’s Web site. He is a professor of Phonetics and Linguistics at University College London (United Kingdom).
The video starts with the given starting numbers and the next scene has all the possible numbers in the blank cells except for those used in the same row, column or block. As new numbers are inserted, the remaining unchosen candidates disappear. (A whole lot of erasin’ going on!)
Perhaps it would better mirror the solving reality, if the constraints of the digit being anywhere else but there, were highlighted also (and perhaps spoken). Nevertheless, it is an excellent and insightful example of solving a Sudoku puzzle in under 3 minutes.