diff --git a/tools/json-wrangler-prefabs.lua b/tools/json-wrangler-prefabs.lua
new file mode 100644
index 00000000..7f850f12
--- /dev/null
+++ b/tools/json-wrangler-prefabs.lua
@@ -0,0 +1,50 @@
+local json = require("rxi-json")
+
+local input = io.read("*a")
+local json = json.decode(input)
+
+local mode = nil
+if not arg[1] then
+    io.stderr:write("Need arg ('total'/'occurred')\n")
+    return
+elseif arg[1] == "total" then
+    mode = "total"
+elseif arg[1] == "occurred" then
+    mode = "occurred"
+else
+    io.stderr:write("Invalid arg\n")
+    return
+end
+
+local data = {}
+for set = 1,#json do
+    local temp = {}
+    for floor = 1,#json[set] do
+        for fabno = 1, #json[set][floor].prefabs do
+            local fab = json[set][floor].prefabs[fabno]
+            if not data[fab.id] then
+                data[fab.id] = { floors = {} }
+                data[fab.id].type = fab.t
+                for z = 1, #json[set] do data[fab.id].floors[z] = 0 end
+            end
+            if not temp[fab.id] then
+                temp[fab.id] = { floors = {} }
+                for z = 1, #json[set] do temp[fab.id].floors[z] = 0 end
+            end
+                data[fab.id].floors[floor] = data[fab.id].floors[floor] + fab.c
+                temp[fab.id].floors[floor] = temp[fab.id].floors[floor] + fab.c
+            if mode == "occurred" then
+                data[fab.id].floors[floor] = data[fab.id].floors[floor]
+                    - (temp[fab.id].floors[floor] - 1)
+            end
+        end
+    end
+end
+
+for fab, dataset in pairs(data) do
+    io.stdout:write(fab)
+    for _, number in ipairs(dataset.floors) do
+        io.stdout:write("," .. number)
+    end
+    io.stdout:write("\n")
+end