However, trial and error is part of problem solving. Teachers are often tempted to intervene too early or too often, being motivated by their genuine desire to set a student "on the right track" and to avoid floundering. This tendency can be exacerbated by the public character of the computer monitor, which makes the students' work more visible and accessible to intervention by the teacher at all stages compared with the more private medium of paper and pencil. Intervention in students' work at an early stage can be helpful, but it also can thwart students, short-circuiting their own construction of knowledge. Michael Hopkins, the lead teacher at the Saturn School, has had students use technology, such as HyperCard presentations, LEGO Logo projects, and other multimedia programs to produce projects. He cautions: