penup --Command, no inputs. Abbreviation: pu
     This command tells the turtle to raise its pen from the paper, so that
     it does not leave a trace when it moves. In the case of the display
     turtle, there is no physical pen to move mechanically, but the effect
     is the same: any forward or back commands after this point do not draw
     a line. The floor turtle starts with its pen up; the display turtle
     starts with its pen down. Note: the floor turtle will not move on the
     carpet correctly with its pen down; put it on a smooth surface if you
     want to draw pictures.