Programs do not always run properly. Students need to understand how to test and make necessary corrections to their programs to ensure they run properly. Students successfully identify and fix errors in (debug) their programs and programs created by others. Debugging strategies at this level may include testing to determine the first place the solution is in error and fixing accordingly, leaving "breadcrumbs" in a program, and soliciting assistance from peers and online resources. For example, when students are developing a program to control the movement of a robot in a confined space, students test various inputs that control movement of the robot to make sure it behaves as intended (e.g., if an input would cause the robot to move past a wall of the confined space, it should not move at all). (CA NGSS: 3-5-ETS1-3) Additionally, students could test and debug an algorithm by tracing the inputs and outputs on a whiteboard. When noticing "bugs" (errors), students could identify what was supposed to happen and step through the algorithm to locate and then correct the error.