Street Sudoku

Two days ago, I spotted a girl in Lausanne, Switzerland, solving a Sudoku on a street poster; It's actually an advertisement for a swiss game but some folks seem to like doing the Sudoku on much bigger dimensions than a newspaper format: real lift sudokuI spotted this picture in Geneva, it's the second street-sudoku that I saw solved.

How does the size of sudoku changes the way it's solved?

How does the fact that it is embedded in a broader context (being on a poster, in public space...) modifies the way the passers-by can be engaged in such an activity?

Do you play sudoku on walls?

What is funny is that few meters from this poster, one year ago, I also spotted this nice drawings on the ground, did by few kids (which made me think of a street tetris):

a real tetris?