I'm making this Pythagoras Theorem Calculator in Python 3.3.2.

I made print over several lines so that I could make a diagram:

print("Welcome to the Pythagoras Theorem Calculator, powered by Python!")
print("Below are the values a, b and c. You will need to input these values after.")
print('''| .|   .|     .
side a|       . side c|         .|           .|_____________.side b''')

As you can see above, three apostrophes were needed instead of the speech marks. Why is this so? Is it an escape character? (I've tried searching on Google: http://bit.ly/15a4zes)

The three quotes allows you to make a string on multiple lines. It avoids you to add \n everywhere or doing multiple print statements.

Threes quote strings are also used recommended to make documentation, see the PEP 257 convention (see also comments of this post)