'''
Drawing lines pixel by pixel is not the most efficient way of doing so. 
Write a program that draws a diagonal line using the writer's drawLine 
function.
'''

pen.drawLine (x1, y1, x2, y2, c)

'''
The first two arguments (`x1` and `y1`) indicate the origin of the line. 
The next two arguments (`x2` and `y2`) are the coordinates of the end of 
the line. The last argument (`c`) is the colour of the line. 
'''