Objective-C Object Messaging

[receiver message]
[receiver message:argument]
[receiver message:arg1 argument2:arg2]
int status = [receiver message];
[receiver makeGroup:group, memberOne, memberTwo, memberThree];

[rectangle draw]
[rectangle setColor:blue]
[rectangle setStrokeColor:blue andThickness:2.0]
double length = [rectangle circumference];
[NSArray arrayWithObjects:one, two, three, nil];