These days we are hit with information from all directions and have to constantly change focus, switch between tasks. Multitasking maybe more efficient for computers but I don’t think this applies to humans. Not only is it lees efficient but it is also more stressful. Singletasking does not mean you do only one task per day, it is a way of prioritizing your task list. You will be surprised how quickly that list gets reduced in size.
I created a template from the picture in the Lifehacker article if you want to try it out, when printing select 8 pages per sheet on the bottom right of the print window.