your code
diver(300,300,1500);
submarine(50,400);
oxygen(250,50,1500);
star(500,400,"red");
urchin(250,300);
urchin(250,350);
urchin(250,250);
urchin(300,250);
urchin(350,250);
urchin(300,350);
urchin(350,350);
urchin(400,350);
urchin(450,350);
urchin(500,350);
urchin(400,250);
urchin(400,200);
urchin(400,150);
urchin(400,100);
urchin(500,300);
urchin(500,250);
urchin(500,200);
urchin(500,150);
urchin(500,100);
star(50,50,"green");
urchin(500,50);