circlePlat

local dia = 62

local x = 0
local z = 0
local dirf = 0

function SelectBlock()
    while true do
        for i = 1, 16 do
            if turtle.getItemCount(i) > 0 then
                turtle.select(i)
                return
            end
        end
        print("Out of blocks, press enter to continue")
        read()
    end
end

local l = 0
local c = 0
while l <= (dia * 2 + 2) do
    for n = 1, l do
        turtle.forward()
        if dirf % 4 == 0 then
            x = x + 1
        elseif dirf % 4 == 1 then
            z = z + 1
        elseif dirf % 4 == 2 then
            x = x - 1
        elseif dirf % 4 == 3 then
            z = z - 1
        end
        if math.sqrt((x*x)+(z*z)) <= dia then
            SelectBlock()
            turtle.placeDown()
        end
    end
    turtle.turnRight()
    dirf = dirf + 1
    c = c + 1
    if c % 4 == 0 or c % 4 == 2 then
        l = l + 1
    end
end