Logic Masters Deutschland e.V.

Standard Sudoku Rules apply to the final numerical layout.

The Sudoku grid is a petri dish divided into 81 squares in which virions (the term for single units) of a virus have been contained and observed as they move and feed. (Yes, technically viruses do not feed, but this is Sudoku, not Medical School.)

This virus moves one square at a time in any direction, provided there is a food energy source rated exactly one digit lower than the digit the virus is on. For example, if a virion is on a 6, it must be able to move to a 5 one square away. Virions that can do this are considered alive and well, and can be found on the White Squares.

A virion unable to move one square to the next lower digit is in danger of decay. But if it can move one square to a 9, a supervirus, it will be re-energized. Decaying virions that can move to a 9 are on Yellow Squares.

A virion that cannot move to the next lower digit nor to a 9 is a dead virion. Those are marked by the Red Squares.

And in case you were curious, the researchers noted that even the supervirus 9's were not exempt. If they could not consume an 8 one square away, and could not find another 9 for re-energizing, they would decay and the square would turn Red.

Some of the virions left behind biochemical debris as they moved, and you can see their Trails on the petri dish. Some clearly end as the virus began decaying; but some are still on the move, but which end is the start of the path is still being researched.

In Summary:

White Squares: A square with the next lowest digit can be found directly adjacent.

Yellow Squares: No adjacent squares contain the next lowest digit, but at least one adjacent square does contain a 9.

Red Squares: None of the adjacent squares contains the next lowest digit or a 9. Total dead end. And even 9's must follow this rule.

Grey Trails: Numbers descend by one, from one end of the trail to the other.

*****

Setter's Diary :: May 19, 2020 :: While public reception to the first Virus Sudoku was minimal, I personally had fun test-solving it and decided to follow up with a second one (the grids are painfully easy to make). I did work harder on this one at keeping the grey trails minimal and a bit more obscure in their usefulness, so we'll see how it goes.