diff --git a/cargo-elevator.lua b/cargo-elevator.lua
new file mode 100644
index 0000000..6aadb4b
--- /dev/null
+++ b/cargo-elevator.lua
@@ -0,0 +1,165 @@
+-- program to manage a cargo elevator
+-- yes, i am aware i could just use the computer to transfer packages at this
+-- point, but where's the fun in that?
+
+local FLOORS = {
+    {
+        match = function (input)
+            local first_char = string.sub(input, 1, 1)
+            return first_char == "A" or first_char == "W"
+        end,
+        detect = function ()
+            return redstone.getInput("top")
+        end,
+        call = function ()
+            redstone.setOutput("top", true)
+            os.sleep(0.5)
+            redstone.setOutput("top", false)
+        end,
+        storage = "create:item_vault_17",
+        elevator_storage = "create:portable_storage_interface_11",
+    },
+    {
+        match = function (input)
+            local first_char = string.sub(input, 1, 1)
+            return first_char == "F"
+        end,
+        detect = function ()
+            local relay = "redstone_relay_21"
+            return peripheral.call(relay, "getInput", "top")
+        end,
+        call = function ()
+            local relay = "redstone_relay_21"
+            peripheral.call(relay, "setOutput", "top", true)
+            os.sleep(0.5)
+            peripheral.call(relay, "setOutput", "top", false)
+        end,
+        storage = "create:item_vault_18",
+        elevator_storage = "create:portable_storage_interface_8",
+    },
+    {
+        match = function (input)
+            local first_char = string.sub(input, 1, 1)
+            return first_char == "L"
+        end,
+        detect = function ()
+            local relay = "redstone_relay_22"
+            return peripheral.call(relay, "getInput", "top")
+        end,
+        call = function ()
+            local relay = "redstone_relay_22"
+            peripheral.call(relay, "setOutput", "top", true)
+            os.sleep(0.5)
+            peripheral.call(relay, "setOutput", "top", false)
+        end,
+        storage = "create:item_vault_19",
+        elevator_storage = "create:portable_storage_interface_9",
+    },
+    {
+        match = function (input)
+            local first_char = string.sub(input, 1, 1)
+            return first_char == "E"
+        end,
+        detect = function ()
+            local relay = "redstone_relay_23"
+            return peripheral.call(relay, "getInput", "top")
+        end,
+        call = function ()
+            local relay = "redstone_relay_23"
+            peripheral.call(relay, "setOutput", "top", true)
+            os.sleep(0.5)
+            peripheral.call(relay, "setOutput", "top", false)
+        end,
+        storage = "create:item_vault_20",
+        elevator_storage = "create:portable_storage_interface_10",
+    },
+}
+
+local SLEEP_T = 5
+
+local PKG_QUEUE = {
+    insert = function (self, floor_i)
+        local is_in = function (item, list)
+            for _, l_item in ipairs(list) do
+                if l_item == item then return true end
+            end
+            return false
+        end
+        if not is_in(floor_i, self.queue) then
+            table.insert(self.queue, floor_i)
+        end
+    end,
+    check_floors = function (self, floors)
+        for i, floor in pairs(floors) do
+            if #(peripheral.call(floor.storage, "list")) > 0 then
+                self:insert(i)
+            end
+        end
+    end,
+    check_cargo = function (self, inv, floors)
+        for slot, item in pairs(peripheral.call(inv, "list")) do
+            local item_detail = peripheral.call(inv, "getItemDetail", slot)
+            for i, floor in ipairs(floors) do
+                if item_detail.package ~= nil and
+                    floor.match(item_detail.package.getAddress()) then
+                    self:insert(i)
+                    break
+                end
+            end
+        end
+    end,
+    transfer_all = function (self, src, dest, floors)
+        -- assumption: this always transfers into the cargo box
+        for slot, item in pairs(peripheral.call(src, "list")) do
+            local item_detail = peripheral.call(src, "getItemDetail", slot)
+            for i, floor in ipairs(floors) do
+                if item_detail.package ~= nil and
+                    floor.match(item_detail.package.getAddress()) then
+                    self:insert(i)
+                    peripheral.call(src, "pushItems", dest, slot)
+                    break
+                end
+            end
+        end
+    end,
+    transfer_matching = function (self, src, dest, match_f)
+        -- assumption: this always transfers out of the cargo box
+        for slot, item in pairs(peripheral.call(src, "list")) do
+            local item_detail = peripheral.call(src, "getItemDetail", slot)
+            if item_detail.package ~= nil and
+                match_f(item_detail.package.getAddress()) then
+                peripheral.call(src, "pushItems", dest, slot)
+            end
+        end
+    end,
+    get_next_floor = function (self)
+        return table.remove(self.queue, 1)
+    end,
+    queue = {},
+}
+
+function run (floors, queue, first_run)
+    local next_floor = nil
+    queue:check_floors(floors)
+    for i, floor in pairs(floors) do
+        if floor.detect() then
+            if first_run then
+                queue:check_cargo(floor.elevator_storage, floors)
+            end
+            queue:transfer_all(floor.storage, floor.elevator_storage, floors)
+            queue:transfer_matching(
+                floor.elevator_storage, floor.storage, floor.match
+            )
+            next_floor = queue:get_next_floor()
+        end
+    end
+    if next_floor ~= nil then
+        floors[next_floor].call()
+    end
+    os.sleep(SLEEP_T)
+    return run(floors, queue, false)
+end
+
+if arg ~= nil and arg[1] == "run" then
+    run(FLOORS, PKG_QUEUE, true)
+end