How can we explain. . .
It sometimes happens that M. Pathfinder runs backwards or spins in place when using the program in slot #1(even though the program instruction is to turn on both motors). Just as in the Wall Hugging Mouse, the answer lies in wiring rather than in the program. If this happens, remind students of what happened when they switched the wire on the Wall Hugging Mouse and have them reposition the wires either on the RCX or to the motors. To reposition the wires students will have to rotate the bricks attached to the connector wires 90º or 180º.
About running a program
There are two ways to run a program—by pressing the Run (green) button on the RCX or by clicking the Run button on the screen.
Pressing the Run button on the RCX runs the selected program. Pressing it once starts the program as indicated by the running person icon in the display window. Pressing the Run button again, stops the running program.
Clicking the Run button on the screen starts the selected program. The RCX must be within communication range with the IR tower. This allows you to track the running program and to get information about the state of sensors and motors. (See the RCX Sensor Link Wizard section in the Help menu.)