Using the Pen_down and Pen_up commands in conjunction with moving your Sprite lets you draw connected and unconnected lines. ACTIONS Toolkit - scroll down to DRAWING section for pen commands. Using the grid as a background can be helpful for moving your sprite to the start and end positions of your lines.
# ACTIONS Toolkit - scroll down to DRAWING section
#Add a sprite and position it at the start of the line
sprite = codesters.Sprite("codester")
#Put the pen down
#Move the sprite to draw a line ( .go_to or .glide_to
#draw a connected line by moving the sprite again
# put the pen up - move - pen down to draw an unconnected line