2) Then move the box at right bottom corner up and shift the bottom row boxes toward right.
3) Now we can fill up a yellow dot with a box with the 'alive' path to the boxes at top.
4) Here is the tricky step. We will build a door here. Move the 2 boxes at right top corner like this:
5) And then this:
6) And then shift the top row boxes toward right. Now you can see there is a door at right hand side constructed by 3 boxes. Relocate the red box at left hand side.
7) Move one box from the door towards left.
8) Repeat step 4, make the door again.
9) Now you can fill up yellow dots at left hand side.
10) Re-arrange the boxes at right hand side and move one box from the bottom.
11) Shift the bottom row towards right.
12) Fill two more yellow dots.
13) Make the door again! (And shift the bottom row towards right.)
14) Nothing difficult here, done.
