diff --git a/compacting-storage.lua b/compacting-storage.lua
new file mode 100644
index 0000000..5bedc20
--- /dev/null
+++ b/compacting-storage.lua
@@ -0,0 +1,153 @@
+-- Program to control a compacting storage made with create.
+
+-- NOTE: set block -> ingot refresh amount higher than the level desired in
+-- this program to prioritize using available resources before generating
+-- new ones
+
+-- constants
+
+local INVENTORY = ""
+local SLEEP_TIME = 5
+local ITEM_TYPES = { "iron", "copper", "zinc", "gold", "electrum" }
+local PRIORITY = { "ingot", "block", "nugget" }
+
+function stacks (num)
+    return 64 * num
+end
+
+-- TODO map targets to specific relays
+local target = {}
+for _, type in ipairs(ITEM_TYPES) do
+    target[type] = {
+        "nugget" = { stacks(4), stacks(8) },
+        "ingot" = { stacks(4), stacks(8) },
+        "block" = { stacks(4), stacks(1000) }
+    }
+end
+
+-- Map types of conversions to specific faces
+local convert = {}
+convert["nugget_to_ingot"] = "front"
+convert["ingot_to_block"] = "top"
+convert["block_to_ingot"] = "back"
+
+function sum_items (inv)
+    -- organize list of item, count into item_type: (count_N, count_I, count_B)
+    -- item name will be in form `{mod}:{item_type}_{form}`
+    local result = {}
+    for _, type in ipairs(ITEM_TYPES) do
+        result[type] = {}
+    end
+    for slot, item in pairs(inv.list()) do
+        local type, form = item.name:match".-:(%l-)_(%l*)"
+        if result[type][form] == nil then
+            result[type][form] = item.count
+        else
+            result[type][form] = result[type][form] + item.count
+        end
+    end
+    return result
+end
+
+-- basic actions
+function request (item_type, conversion_type)
+    target[item_type].setOutput(convert.conversion_type, true)
+    os.sleep(0.05)
+    target[item_type].setOutput(convert.conversion_type, false)
+end
+
+function request_multiple (item_type, conversion_type, count)
+    if count < 1 then return end
+    if count == 1 then
+        return request(item_type, conversion_type)
+    else
+        request(item_type, conversion_type)
+        os.sleep(1)
+        return request_multiple(item_type, conversion_type, count - 1)
+    end
+end
+
+-- fundamental actions
+-- assumptions: a drain or fill of 1 will increase or decrease the amount of
+-- that item by 63
+function drain (type, form, amount)
+    local conversion = nil
+    if form == "nugget" then
+        conversion = "nugget_to_ingot"
+    elseif form == "ingot" then
+        conversion = "ingot_to_block"
+    end
+    request_multiple(type, conversion, amount)
+end
+
+function fill (type, form, amount)
+    local conversion = nil
+    if dest == "block" then
+        conversion = "ingot_to_block"
+    elseif dest == "ingot" then
+        if src == "nugget" then
+            conversion = "nugget_to_ingot"
+        elseif src == "block" then
+            conversion = "block_to_ingot"
+        end
+    end
+    request_multiple(type, conversion, amount)
+end
+
+-- making the decision what to do
+-- assumptions: a drain or fill of 1 will increase or decrease the amount of
+-- that item by 63
+function should_drain (type, counts)
+    local drain_form, amount = nil, 0
+    for _, form in ipairs(PRIORITY) do
+        local diff = counts[form] - target[type][form][2]
+        if diff > 0 then
+            amount = math.ceil(diff / 63)
+            drain_form = form
+            return drain_form, amount
+        end
+    end
+end
+
+function should_fill (type, counts)
+    local fill_dest, fill_src, amount = nil, nil, 0
+    for _, form in ipairs(PRIORITY) do
+        local diff = target[type][form][1] - counts[form]
+        if diff > 0 then
+            if fill_dest == nil then
+                amount = math.ceil(diff / 63)
+                fill_dest = form
+            end
+        else
+            fill_src = form
+        end
+        if fill_src ~= nil and fill_dest ~= nil then break end
+    end
+    return fill_dest, fill_src, amount
+end
+
+function decide_action (type, counts)
+    -- using the levels of each form of the item, decide what to do
+    for _, form in ipairs(PRIORITY) do
+        local drain_form, drain_amt = should_drain(type, counts)
+        local fill_dest, fill_src, fill_amt
+        if drain_form ~= nil then
+            drain(type, form, drain_amt)
+        elseif fill_dest ~= nil then
+            fill(type, form, fill_amt)
+        end
+    end
+end
+
+while true do
+    -- 1. Sum items in inventory and organize by item type
+    local items = sum_items(peripheral.wrap(INVENTORY))
+
+    -- 2. take one action for each item type per cycle
+    for item_type, counts in pairs(items) do
+        decide_action(item_type, counts)
+    end
+
+    -- sleep until next cycle
+    os.sleep(SLEEP_TIME)
+end