Normal sudoku rules apply, and shading cells will help you solve the puzzle! Clues outside the grid show the sums of digits in shaded cells. The groups of shaded cells must be separated by at least 1 unshaded cell. In addition - one of the following rules applies: Rhino rule (cells that are n cells over and n+1 cells up cannot have the same digit for each value of n); Camel rule: identical cells cannot be an extended knight's move apart (a regular knight's move is 1:2 , a camel move is 1:3); Elephant rule (cells 1 or 2 steps diagonally apart cannot have an identical digit).