Didik is a schoolboy who has expertise and does what he really likes i.e. making a straight vertical line. During school, he often had problems with the teachers because he did not master the subjects being taught and could only draw his favorite straight vertical  line. Everyone in school mocked his skills. Then when he became an adult, he gave up his interest and expertise in the vertical line and forgot about it. But it was too late for him to realize that his vertical line skills could have a big impact on his life.