Logic Masters Deutschland e.V.

This puzzle was made for a weekly Scojo prompt: "A Secret Surprise When You Flip It Upside Down". I wanted to make a puzzle which can not only be solved in two directions, but also feels dynamic in a genuine "flipping it upside down" way. This was the result--it's quite bizarre, but I hope you enjoy it!

• This puzzle can be solved as presented, or with the grid rotated by 180 degrees.
• Standard sudoku rules apply: fill every row, column, and box with the digits 1 to 9.
• Marble run: each ball (circle) with a corner clue is a 'given digit' whose position has yet to be determined. Their final positions are essentially determined by 'gravity'. More precisely, the positions are determined as follows:
  • If there is no obstacle below a ball, it falls downwards (at a speed of "one row per unit time"). If there is an obstacle in the cell directly below the ball, its behaviour is determined by the type of obstacle.
  • There are three types of obstacles:
    • If a ball reaches a platform (a brown horizontal line), it becomes stationary.
    • If a ball is in a cell immediately above a stationary ball, it also becomes stationary.
    • Balls roll downwards along 'ramps' (brown diagonal lines), always by 45 degrees, and at a speed of "one row per unit time". A ball on a ramp will become stationary if the next cell along the ramp is occupied by a stationary ball.
• Clarification: the balls are assigned a speed of "one row per unit time" to resolve any ambiguities between balls which interact with one another.

The following example grid will hopefully clarify the rules.

Click here to solve this puzzle on PuzzleTV for an actual rotating grid.

Click here and here to solve the puzzles in sudokupad (for solution check).