for example

coordinator Shape, Screen {

mutex {adjustLocation, getX};

mutex {adjustLocation, getY};

}

public class Shape {

protected int x = 0;

protected int y = 0;

protected int w = 0;

protected int h = 0;

int getX() { return x; }

int getY() { return y; }

int getWidth(){ return w; }

int getHeight(){ return h; }

void adjustLocation() {

x = longCalculation1();

y = longCalculation2(); }

...