Question

face. If you touch a face 6. Consider a 4x 4 then it chang n itchagrid with each position containing a happy or sa happyor hce and all neighbouring faees those that rom sad to share an edge sad to touching the For example, the right diagram is obtained from the iet diagram by touching the top left face. y or happy to sad. F (i) Beginnin (i) Beginnin g with all sad faces, as in the left diagram, is it possible to change this t ng with any initial setup of happy and sad faces, is it possible to change this to appy faces by touching the faces in a particular sequence? all happy faces by touching the faces in a particular sequence?

Answer 1

Yes

1) it is possible to change all happy sad faces to happy faces by touching the first row middle two columns

Then first row last column

Then second row completely

Then 3rd row completely will make you to turn to all happy faces.

2) no it is not possible as a face can be changed to other face if we try to make a mixed combination of faces to all happy faces...

So there is an exceptional case to do it but

Generally as most of the cases it is not possible to make all happy faced with combination of happy and sad faces

So the answer would be no.