Shaft

t = turtle

function distanceInput()
    print("Input Distance")
    num = io.read()
    num = tonumber(num)
    return num
end
function fuel(distance)
    t.refuel()
end
function hole(distance)
    while distance > 0 do
        if t.detectUp() then
            t.digUp()
            t.up()
        else
            t.up()
        end
    distance = distance - 1
    end
end
function dforward()
    if t.detect() then
        t.dig()
        t.forward()
    else
        t.forward()
    end
end
function turn()
    t.turnLeft()
end
function turnR()
    t.turnRight()
end
function mineLayer()
    if mark then
        dforward()
        turn()
        dforward()
        dforward()
        turn()
        dforward()
        dforward()
        turn()
        dforward()
        turn()
        dforward()
        turnR()
        dforward()
        turn()
        dforward()
        t.digDown()
        t.down()
        turn()
    else
        dforward()
        dforward()
        turn()
        dforward()
        dforward()
        turn()
        dforward()
        t.dig()
        turn()
        dforward()
        dforward()
        t.digDown()
        t.down()
        turn()
    end
end
function mine(distance)
    mark = true
    dforward()
    turn()
    t.digDown()
    t.down()
    while distance > 0 do
        mineLayer(mark)
        distance = distance - 1
        mark = not mark
    end
    t.up()
    t.placeDown()
end
function spiral()
    distance = distanceInput()
    fuel(distance)
    print("3x3 Spiral Initiated; No further input required")
    mine(distance)
end

spiral()