The art of the 20th century is saturated with many visual styles created under the influence of numerous events in the world. One of them is the op-art which appeared in the mid 20th century. Op-art artists try to create so-called "optical madness''. With the use of rhythmic alignment of lines, shapes, and colors, an optical illusion is achieved. By doing so they are trying to include the spectator into the game. There is no focal point in their works. The most renowned world op-art artists are Victor Vasarely and Bridget Riley. Vasarely is dealing with the multiplication of his artistic works and believes that in this sense the art approaches a larger set of people, but Bridget strives for objectivism by not leaving her personal handwriting. Vasarely's work "Zebra" is considered to be the first-ever op-art piece while he is thought to be the "grandfather" of the movement. The most famous Croatian op-art artists are Miroslav Šutej and Ivan Picelj. Since they started with their work at the time filled with many changes and new situations, they weighed for something new. In this thesis, their reproductions were used as motivation in the art class. Five reproductions were selected for five different lectures in the first four grades of elementary school. Reproductions are tailored to the art language that is familiar to students at a certain age. Classes of all levels were included, from the first to the fourth. Given the year students were in, most of the visual problems underwent change. The rhythm was represented in all teaching units. Even the students of the first year have created op-art works. Art techniques include colored felt-tip pens, tempera paint, drawing ink, collage paper and colored paper. Most of the works are independent work. In one lecture, the students worked in teams. All 113 works were assembled in a large folder. In this paper, apart from the preparation for the lesson and the thematic part about op-art and its components, there are analyses of student work. A number of the students' works were analyzed by visual language and thematic analysis. The criteria also include the efficacy of the given educational tasks.