Yesterday afternoon the boys were let loose to run in the yard while I cleaned up the kitchen (an unending task). After a time they wandered out of my immediate line of sight so I ventured out to check on them.
Turns out P had mastered the ladder on the climbing structure and he and O were taking turns climbing up and going down the slide.
This kept the boys happily occupied for nearly forty five minutes, until they were pink from the heat and I insisted they come in and have some water and a light snack before swimming lessons.