Sometimes you need your little child to play contentedly nearby while you do some work. To the rescue: complex toy combinations. Early childhood teachers, parents and grandparents too, have noticed that the more complex the play materials, the longer the children will play.
The rule of thumb is more than three items.
My all-time favorite combo is water, sand, shovel and pail. My next favorite is a small table, a big towel, a basin of water, a small teapot and many small cups. You can add a colander or a funnel. A small, play house space lasts longer with dress-up clothes, a small table and dishes with play food. Bread dough lasts longer with raisins, nuts, forks and rolling pins. Sandbox play lasts with a dump truck, digger, sticks, pine cones and small stones. What works for you?
Children are natural physicists, so things that fall and roll and pour and prod and hurl and can otherwise be put into motion will hold their interest, as well as things they can stack that balance then fall. The more chances they have to play without help or intervention, the more skilled they will become. But some children need a boost from an adult to get them going, and intermittent boosts to keep them going.