This.
There is a minor syntax error:
>>> if the_world_is_flat:
should be
>>> if (the_world_is_flat == 1):
But I don't think this should have been coded in the console. The console is mainly used for calling the functions you make in the upper box [can't remember its name now >_>]
Make something in the upper box that says
def flatWorld()
isFlat = 1
if (isFlat == 1):
print "be careful not to fall off!"
Then in the console, type this:
>>> flatWorld()