Think outside the box

Think outside the dots is still in use, although it is far less common than think outside the box. Here is a more recent example of think outside the dots from the Trenton Evening Times of 28 February 2010:
Challenge brings success
Architect J. Robert Hillier says you have to “think outside the dots”
[...]
“It’s a great puzzle,” he explains, brandishing a pencil and solving the challenge. “But you have to go outside the dots. You have to extend the line beyond the rectangle. That the trouble with so many people.
“When people are confronted with the puzzle—any puzzle—they try to stay inside those dots. And the key to beating it,” Hillier adds with a smile, “is to go outside.”
The box wording can be traced to a 26 October 1969 newspaper column by preacher and self-help guru Norman Vincent Peale. Peale was enormously popular and influential, and his column would have been widely syndicated and read, and he is certainly responsible for much of the phrase’s popularity. Although, as with outside the dots, he doesn’t use the full phrasing of think outside the box:
There is one particular puzzle you may have seen. It’s a drawing of a box with some dots in it, and the idea is to connect all the dots by using only four lines. You can work and work on that puzzle, but the only way to solve it is to draw the lines to [sic] they connect outside the box. It’s simple, once you realize the principle behind it. But if you keep trying to solve it inside the box, you’ll never be able to master that particular puzzle.
That puzzle represents the way a lot of people think. They get caught up inside the box of their own lives. You’ve got to approach any problem objectively. Stand back and see it for exactly what it is. From a little distance, you can see it a lot more clearly. Try and get a different perspective, a fresh point of view. Step outside the box your problem has created within you and come at it from a different direction.
The full phrase think outside the box dates to a few years later and the September 1971 issue of the journal Data Management:
THINK OUTSIDE THE BOX
If you have kept your thinking process operating inside the lines and boxes, then you are normal and average, for that is the way your thinking has been programmed. Unfortunately, we have accepted thought process limitations that are artificial. They are man-made and do not exist in reality.
And as with the dots version, within a decade the phrase think outside the box could be used without explicit reference to the puzzle, assuming the readers would understand what was meant. From a syndicated medical column of 23 March 1978 by Dr. Robert Mendelsohn:
Some of my best teachers have been those who utilize the techniques of shock and surprise to rouse me out of conventional habits of thought, forcing me to question accepted teaching and stimulating me to “think outside the box.”