I need help to understand a question in combinatorics.
One corner square in a $3 \times 3$ grid is painted black, the other
squares are white. In one move you can change color in all squares in
a row or in a column. Can you get all the squares black after a number
of such moves?Hint: Study the number of black squares among the four corner squares
Does this regard a Rubiks cube? I cannot see other option that that, given the expression "in one move".
If not, any hints appreciated!
[[ Not looking for Solutions , only want Clarification on the Question ]]
Best Answer
It is a Planar Puzzle , not a Cubic Puzzle (Definitely not Rubic)
Putting in other words & Using Images may aid here , hence I will try that :
No Colouring :
Starting Position :
Playing with the move to the top row :
Ending Position :
Solution :