Single pointed concentration

"We should not keep changing our object of concentration. When you decide on one thing, stick to it whatever happens. There's no value in digging shallow wells in a hundred places. Decide on one place and dig deep.... Even if it's a long route, your perseverance will make it short. Our aim is to make the mind steady, so it is immaterial what object we take. Anything can take you to the goal, because you are not concentrating on the object for the sake of the object but for the sake of your goal." - Sutra 1:32 Patanjali