I bought a python book recently and an trying to learn. There is a
question that asks the user to:

Write a program that allows the user to draw a house using just 5 mouse clicks;
Step 1 - First 2 clicks define the opposite corners
Step 2 - Third click indicates the middle of the top edge of a door
(1/5 of the width of the house
Step 3 - Forth click is the position of a centre of a window.  the
window is square. Half the width of the door
Step 5 - Fifth is the peak of the roof.  Obviously the side extend to
the two corners of the house.