Type in the instructions below and then type road to check that
they draw the two sides of a road. The instructions pu and pd are short for
PenUp and PenDown. They allow you to move the turtle without drawing a line.
Can you add some instructions to draw the dashed line down the centre?
To road
rt 90
fd 100 lt 90
pu fd 40
lt 90
pd fd 100
End
How about drawing a dual-carriageway?