To move the green wall back, you must make almost all its rectangles glow green. Notice how when you touch a rectangle, it lights up as well as the four rectangles above, below, to the left and to the right of the light you touched.
You have to light it up column by column, starting on the far left or the far right. Light up the first column, then move to the THIRD column to fill up the dark spots in the SECOND column. Then move to the FOURTH column to take care of the THIRD, and so on and so on.
Fortunately, to get the wall moved back, not ALL of the rectangles must be lit up, but most of them should be.