require("a")
 
size = 10
 
function refuel()
    for i = 1,16 do
    turtle.select(i)
    print(turtle.getFuelLevel)
    if turtle.getFuelLevel < 7 then
        turtle.refuel(1)
    end
end
end
 
function mine()
    turtle.dig()
    turtle.digUp()
    turtle.digDown()
    refuel()
    suc = turtle.forward()
    return suc
end
 
function walk (len)
    x = 0
    while x < len do
        if mine() then x = x + 1 end
    end
end
 
 
 
for i = 0,size do
    walk(size - i)
    turtle.turnRight()
    walk(size - i)
    turtle.turnRight()
end