# purpose:
# - write functions
# - import existing modules and use existing functions
# - call function, pass by value
# - return and print
#
# - introduce docstring
#
# activity:
# - refer to pseudo practice (http://www.cs.virginia.edu/~up3f/cs1111/inclass/inclass-pseudocode.html)
# - write a module with multiple functions
#   -- create a python file, named simplegrid.py
#   -- in simplegrid.py, write 2 functions to solve the grid problems
#      --- is_diagonal(width, tile)
#      --- is_edge(width, height, tile)
# - create another python file, called grid_testdriver.py
#   -- import the simplegrid module in to grid_testdriver.py
# - call existing functions from grid_testdriver.py
#   -- have test cases to call is_diagonal and is_edge