This childrens picture book centers on playing seesaw to demonstrate the science of leverage. It is illustrated by Akiyama Tadashi (1964), a Japanese childrens picture book writer, cartoon and manga artist. Children will learn basic lever mechanism by comparing which one is heavier and which one is lighter.This childrens picture book centers on playing seesaw to demonstrate the science of leverage. It is illustrated by Akiyama Tadashi (1964), a Japanese childrens picture book writer, cartoon and manga artist. Children will learn basic lever mechanism by comparing which one is heavier and which one is lighter.