Recent research on studio thinking has indicated that artmaking experiences can cultivate learners’ Studio Habits of Mind (SHoM) by supporting them to work and think like artists. While creating visual arts curriculum for young children, how to engage them with playful and enjoyable art studio experiences and at the same time cultivate their artistic expression and imagination has become a core issue for teachers in preschools. For more than twenty years, the artist-teachers of the Children’s Art Museum in Taipei (CAMIT) have been designing art studio curricula for young children and implementing the curricula in local preschools. This research uses the case study approach to analyze their art studio curriculum, Magic Lines. I chose to study this particular curriculum for its easy implementation—preschool teachers without visual arts training can also teach the lesson in their own classroom. This research interrogates issues related to the teaching strategies that the teachers implemented and the SHoM cultivated through the curriculum. The data collected includes observation, interviews, and document analysis. I observed the art studio activity, interviewed professionals who design the curriculum and teach the activities. I also collected documents such as the lesson plans and images of children’s artworks. The data were coded, analyzed, and interpreted according to the research questions asked. In the Magic Lines lesson activities, the artist teacher guided students to explore possibilities of creating new colors by using pastels. The conclusion explains how artist-teachers with background in the visual arts use both professional artmaking and art teaching approaches to scaffold the activities for children to create abstract artworks using colors. Storytelling was used as an important approach to engage children through the lesson. The conclusion also discusses how artist-teachers use organic lines and shapes to encourage children to observe and envision creatively like artists. Tips for preschool teachers to teach the lesson are also provided at the end of this paper.