diff --git a/polymer/eduke32/source/lunatic/util/cmpart.lua b/polymer/eduke32/source/lunatic/util/cmpart.lua
new file mode 100755
index 000000000..625ccfbe4
--- /dev/null
+++ b/polymer/eduke32/source/lunatic/util/cmpart.lua
@@ -0,0 +1,100 @@
+#!/usr/bin/env luajit
+
+local io = require("io")
+local os = require("os")
+local string = require("string")
+local format = string.format
+local table = require("table")
+
+local B = require("build")
+
+local ffi = require("ffi")
+local C = ffi.C
+
+ffi.cdef[[
+int memcmp(const void *s1, const void *s2, size_t n);
+]]
+
+local fn1, fn2 = arg[1], arg[2]
+local noOnlyLeft = (arg[3]=="-l")  -- don't show diff lines where left has tile, right hasn't
+
+local function err(str)
+    io.stderr:write(str, "\n")
+    os.exit(1)
+end
+
+local function printf(fmt, ...)
+    io.stdout:write(string.format(fmt, ...), "\n")
+end
+
+if (not fn1 or not fn2) then
+    err("Usage: "..arg[0].." </path/to/tilesXXX.ART> </path/to/tilesYYY.ART> [-l]")
+end
+
+local af1, errmsg = B.artfile(fn1)
+if (errmsg) then
+    err(errmsg)
+end
+
+local af2, errmsg = B.artfile(fn2)
+if (errmsg) then
+    err(errmsg)
+end
+
+-- Check for same start/end
+
+if (af1.tbeg ~= af2.tbeg) then
+    err("tile starts differ: "..af1.tbeg.." "..af2.tbeg)
+end
+
+if (af1.tend ~= af2.tend) then
+    err("tile ends differ: "..af1.tend.." "..af2.tend)
+end
+
+-- Compare the two ART files
+
+local SIZEOF_PICANM = ffi.sizeof(af1.picanm[0])
+
+for i=0,af1.numtiles-1 do
+    local sx1, sx2 = af1.sizx[i], af2.sizx[i]
+    local sxdif = (sx1 ~= sx2)
+
+    local sy1, sy2 = af1.sizy[i], af2.sizy[i]
+    local sydif = (sy1 ~= sy2)
+
+    local sizedif = (sxdif or sydif)
+    local picanmdif = (C.memcmp(af1.picanm[i], af2.picanm[i], SIZEOF_PICANM) ~= 0)
+
+    local datadif = false
+    -- compare data
+    if (not sizedif) then
+        local pic1 = af1:getpic(i)
+        local pic2 = af2:getpic(i)
+
+        if (pic1 and pic2 and C.memcmp(pic1, pic2, sx1*sy1) ~= 0) then
+            datadif = true
+        end
+    end
+
+    if (sizedif or picanmdif or datadif) then
+        local strbuf = {}
+
+        local s1str = sx1*sy1==0 and "none" or format("(%d,%d)", sx1, sy1)
+        local s2str = sx2*sy2==0 and "none" or format("(%d,%d)", sx2, sy2)
+        if ((sxdif or sydif) and (not noOnlyLeft or s2str ~= "none")) then
+            strbuf[#strbuf+1] = format("size %s %s", s1str, s2str)
+        end
+
+        if (picanmdif) then
+            strbuf[#strbuf+1] = "picanm"
+        end
+
+        if (not sizedif and datadif) then
+            strbuf[#strbuf+1] = "data"
+        end
+
+        if (#strbuf > 0) then
+            io.stdout:write(i..": "..table.concat(strbuf, ", "), "\n")
+        end
+    end
+end