build.lua

-- Direction enums
LEFT = 0
RIGHT = 1
FORWARD = 3

function go(dir, n)
    -- goes n blocks in direction dir
    -- ends facing direction dir
    if dir == LEFT then
        turtle.turnLeft()
    elseif dir == RIGHT then
        turtle.turnRight()
    elseif dir ~= FORWARD then
        print("Invalid direction: '" .. dir .. "'")
        return
    end

    for i = 1,n do
        turtle.forward()
    end
end

function getBlock()
    -- ensures turtle always has selected block
    while(true) do
        if turtle.getItemCount() == 0 then
            i = turtle.getSelectedSlot()
            turtle.select(i+1)
        else
            break
        end
    end
end

function buildLine(length)
    -- builds a line of blocks below the turtle
    for i = 1,length do
        getBlock()
        turtle.placeDown()
        turtle.forward()
    end
end

function bigSlice(n)
    -- counter clockwise
    for i = 1,n do
        for j = 1,4 do
            buildLine(4)

            go(LEFT, 1)
            turtle.turnRight()
            buildLine(2)

            go(LEFT, 1)
            turtle.turnRight()
            buildLine(1)

            go(LEFT, 1)
            buildLine(2)

            go(RIGHT, 1)
            turtle.turnLeft()
        end
        turtle.up()
    end
end

function medSlice(n)
    for i = 1,n do
        for j = 1,4 do
            buildLine(4)

            go(LEFT, 1)
            turtle.turnRight()
            buildLine(2)

            go(LEFT, 1)
            buildLine(2)

            go(RIGHT, 1)
            turtle.turnLeft()
        end
        turtle.up()
    end
end

function smallSlice(n)
    for i = 1,n do
        for j = 1,4 do
            buildLine(4)

            go(LEFT, 1)
            buildLine(1)

            go(RIGHT, 1)
            buildLine(1)

            go(LEFT, 1)
        end
        turtle.up()
    end
end

turtle.select(1)
bigSlice(1)
-- adjust position for medslice
go(LEFT, 1)
turtle.turnRight()
medSlice(1)
-- adjust position for smallslice
go(LEFT, 1)
turtle.turnRight()
smallSlice(1)