// Draw diamond
NSRectFillUsingOperation(NSMakeRect(knobRect.origin.x + 3, knobRect.origin.y + 6, 1, 1), NSCompositeSourceOver);
NSRectFillUsingOperation(NSMakeRect(knobRect.origin.x + 2, knobRect.origin.y + 5, 3, 1), NSCompositeSourceOver);
// Draw diamond
NSRectFillUsingOperation(NSMakeRect(knobRect.origin.x + 3, knobRect.origin.y + 6, 1, 1), NSCompositeSourceOver);
NSRectFillUsingOperation(NSMakeRect(knobRect.origin.x + 2, knobRect.origin.y + 5, 3, 1), NSCompositeSourceOver);