One friend of mine described to me the concept of vertical thinking versus horizontal thinking.
In short, vertical thinking says "if it isn't working, do it more, harder, faster". Horizontal thinking says "if it isn't working, do something different".
Three examples of vertical thinking are gun control, trying to contact someone by telephone. And nut setter tips that wear out.
Gun control: After outlawing private ownership of guns in Washington DC, violence is at an all time high.
Vertical: Well, then, outlaw assault weapons, close the gun show loop hole, register all guns, outlaw knives and baseball bats, too. Horizontal: Look for the root causes, and start issuing gun licenses to good people. Work on strong families, and cut down on violence on TV.
Contact: I had a case where the battery in my pager went dead. The answering service had a call for me, but I didn't answer the pager.
Vertical: The gal beeped me several times, and then had one of her kids keep dialing my beeper number. Horizontal: I had been sitting next to the telephone at home. She coulda called me at home and I woulda answered on the second ring.
Nut setters: I used to install HVAC. We used a lot of sheet metal screws. I found that the Stanley brand tips from Home Depot wore smooth in less than one install.
Vertical: I bought several more tips. Horizontal: Mentioned this to my boss, who gave me a Malco brand nut setter -- which has lasted for years, for me. Boss was at that moment a horizontal thinker.