Hello Ruby noob alert

I manually draw a line with the pencil tool and select it. If I then have a script with the code below the variable selection contains my line,I know because the clear deselects my line on the screen. My question is how do i get the start and end points of the selected line? I have been reading the google api site, but tbh the code examples are very fragmentry and putting stuff together is hard.

model = Sketchup.active_model
selection = model.selection
selection.clear