In his book NEW THINK, Edward de Bono talks about vertical and lateral
thinking. Vertical thinking begins with a single concept and then proceeds
with that concept until a solution is reached. Lateral thinking refers to
thinking that generates alternative ways of seeing a problem before seeking a
solution. At one point in his book, De Bono explains vertical and lateral
thinking by referring to the digging of holes. He states:

"Logic is the tool that is used to dig holes deeper and bigger, to make them
altogether better holes. But if the hole is in the wrong place, then no
amount of improvement is going to put it in the right place. No matter how
obvious this may seem to every digger, it is still easier to go on digging in
the same place than to start over again in a new place. Vertical thinking is
digging the same hole deeper; lateral thinking is trying elsewhere."

De Bono acknowledges advantages in digging the same hole, admitting that "a
half-dug hole offers a direction in which to expend effort." He elaborates,
"No one is paid to sit around being capable of achievement. As there is no
way of assessing such capability it is necessary to pay and promote according
to visible achievements. Far better to dig the wrong hole (even one that is
recognized as being wrong) to an impressive depth than to sit around
wondering where to start digging." However, De Bono makes the point that many
holes are being dug to an impractical depth, many in the wrong place, and
that breakthroughs usually result from someone abandoning a partly-dug hole
and beginning anew in a different place.

From "Conceptual Blockbusting: A Pleasurable Guide to Better Problem
Solving." James L. Adams. Copyright 1974, 1976. Published simultaneously in
Canada by George J. McLeod Limited, Toronto. This book was published
originally as a part of THE PORTABLE STANFORD, a series of books published by
the Stanford Alumni Association, Stanford, California. This edition first
published by W. W. Norton & Company, Inc. in 1978 by arrangement with the
Stanford Alumni Association.

NEW THINK, Edward de Bono (New York: Basic Books, 1967)

I am collecting books, it seems, simultaneously published in the US and
Canada.  Another example is "A Dictionary of Epithets & Terms Of Address," by
Leslie Dunkling, 1990.