Flowchart creators use diamond shapes () to indicate alternative courses of action. You cannot combine AND and OR operators in a Boolean expression. It is illegal to use a block to contain a single statement. When if-else statements are nested, each else is always paired with the most recent unpaired if. A Boolean expression is evaluated within every while loop to determine whether the loop body will execute. You cannot always use a for loop instead of a counter controlled while loop. A looping structure involves choosing between alternative courses of action based on some value within a program. The do loop checks a value at the "top" of the loop before the body has a chance to execute. Method "nextInt" belongs to Random class. Math class methods can be invoked directly (i.e., no need to create an object)