if turtle.getFuelLevel() < 29 then
	print("need more fuel");
	return;
end;

for k=1,3 do
	for j=1,4 do
		for i=1,3 do
			if k>1 and ( i==2 or i == 3) and j%2==1 then
				turtle.turnRight();
				turtle.dig();
				turtle.turnLeft();
			end;
			turtle.digDown();
			turtle.forward();
		end;
		turtle.turnRight();
	end;
	turtle.down();
end;