Snakes swing themselves around branches of trees. In order not to fall, the snake has to swing alternately front and back along the branches. This is easy to be shown with a vacuum cleaner hose and a couple chair legs.
Children draw three trunks with some branches. Around the trunks and branches they draw three or more snakes. Be careful with the principle of going for along and back along.
The snakes have to be coloured firmly to highlight the contrast with the trees. Colour the trees. Colour the background with chalk pastel and fix the work with hairspray.