Learning Resources STEM Explorers Marble Runners - Skill Learning: STEM - 5-10 Year (LRNLER9307) EachDesign your own marble track using STEM Explorers Marble Runners. Cling back pieces let children build tracks on walls and windows to solve the included STEM challenges. As they build, test and tweak their marble runs, young learners will also strengthen essential kindergarten STEM skills including critical thinking, problem solving and engineering. Set includes 13 track pieces, two balls and 10 double sided, challenge cards. General Information