Logic Masters Deutschland e.V.

Everyone loves a simple 4x4, right? WRONG! This 4x4 is anything but simple. The rules for this 4x4 are almost identical to the rules of Parasitic Destruction. Although Parasitic Destruction is a brilliant construction with beautiful logic, Destructive Can of Worms is an enigma with the sole purpose of being confusing and frustrating. Can you outsmart this tiny puzzle?

1. Place the digits 1-4 once in every row and column.
2. Every circle in the grid must behave as a Chaos Destruction circle and/or a Parasite circle.
3. Chaos Destruction: All given regions must be "destroyed" by making sure they do not contain all the digits 1-4. The grid also consists of four hidden, orthogonally connected regions that each do contain all the digits 1-4. Digits in Chaos Destruction circles represent how many of its orthogonally and diagonally adjacent cells, including itself, belong to both the given and hidden regions where the circle resides (i.e., where they overlap).
4. Parasites: Draw parasites moving orthogonally through the grid that connect all Parasite circles that share the same digit. Parasites may not move diagonally, branch, or cross themselves nor each other, but they may touch themselves and each other otherwise. The start and end of each parasite must occur on distinct circles. Small white rectangles indicate cell borders crossed by a parasite. The grid may contain one or both types of parasites:
   • Larvae must contain a total number of bends equal to the digit in its Parasite circles, and at least one of those bends must occur on a cell where its circle-digit appears outside of a Parasite circle.
   • Adults must contain a total number of bends between each Parasite circle (not counting bends on Parasite circles) equal to the digit in its Parasite circles. Additionally, all the digits an adult crosses are grouped by the hidden regions they belong to, and the sum of all the digits in each group must be divisible by that adult's circle-digit.

You can solve the puzzle on F-puzzles or on SudokuPad.