Big Trees - Ari's attempts to make the world's tallest toy block tower keep falling over, so he tries to get some inspiration from a special field trip to the forest to see the world's tallest trees. When they arrive, the kids are AMAZED to see the huge sequoias, which are so tall, the kids can't even see the top! They try to form a ring around the trees by having the whole class hold hands, but they don't even get close to circling the tree. This makes Ari realize how tall trees are often wide at the bottom, which gives him the perfect idea for his tower: just make it wide at the bottom! Baby Steps - While Elinor and Ari are looking after Ari's baby sister, Miri, in the park, they decide they want to teach her how to walk. But, after they try and try again, Miri still can't seem to be able to walk. Meanwhile, Olive is determined to learn a new roller skate jump, but can't seem to get it. The kids finally realize that sometimes, you can't do things, because your body isn't ready yet. With this new knowledge, they help Miri stand, and Olive gets inspired to practice until she's ready to do her new move!