A variable that is declared within a block can only be referenced within the block. A block is one or more statements enclosed within curly braces (the characters { and }). If a local variable declared in a block has the same name as a global variable declared at the monitor level, or a local variable declared at the action level, the block's local variable hides the global variable or the action's variable, or both if all three have the same name, until the end of the block (the closing }).