3.1.1

There are problems about a robot in a grid with special procedures that don't exist in Snap!:

• The

  MOVE_FORWARD ()

  moves the sprite forward one grid square. (You need to call it repeatedly to move more than one grid square.)
• The

  ROTATE_LEFT ()

  or

  ROTATE_RIGHT ()

  blocks always turn exactly 90 degrees. (They are used only to move a robot in a grid.)
• The

  CAN_MOVE (direction)

  block returns true or false depending on whether or not the robot can move in the input direction without running into a wall or walking off of the maze.

You can read more about these AP language procedures on the Snap! Cheat Sheet in the Robot section at the bottom.