By the end of the second year, children are gaining more and more control over simple movements and integrating these skills into increasingly complex actions. For example, children progress from disorganized scribbling with crayons to more controlled actions like copying simple lines. At this age, many children can also build towers of five or more blocks, which requires coordinating several actions (reaching for a block, grasping the block, placing it on top, and then gently letting go of it).