Cassidy Rippentrop, 15, left, a Harrisburg High School sophomore in the MOD-CL program, and Sheridan Andre, 15, also a sophomore in the MOD-CL program, investigate a fake crime scene as part of a Project Lead the Way principles of biomedical science class, which has both MOD-CL and traditional students in it, Thursday, Sept. 3, 2015, at the Harrisburg High School in Harrisburg, S.D. Harrisburg High SchoolÕs MOD-CL classes allow students to set their own pace for learning, allowing them to gain a better understanding of subjects before they move on to the next lesson.