diff --git a/extra/decomp_logic.py b/extra/decomp_logic.py
new file mode 100644
index 0000000..b8ab57a
--- /dev/null
+++ b/extra/decomp_logic.py
@@ -0,0 +1,179 @@
+import xdis
+import ast
+
+from collections import defaultdict
+
+def main():
+    pyc_filename = 'Randomizer.pyc'
+
+    (
+        version_tuple,
+        timestamp,
+        magic_int,
+        topco,
+        is_pypy,
+        source_size,
+        sip_hash,
+    ) = xdis.load_module(pyc_filename)
+
+    opc = xdis.get_opcode(version_tuple, is_pypy)
+
+    for co in topco.co_consts:
+        if getattr(co, 'co_name', '') == 'update_requirements':
+            bc = xdis.Bytecode(co, opc)
+
+            ops = set()
+            for i in bc:
+                ops.add(i.opname)
+                #if i.opname == 'EXTENDED_ARG' or 'JUMP' in i.opname:
+                #    print(i)
+            #print('\n'.join(sorted(ops)))
+
+            dump(bc)
+
+def mkbool(op, a1, a2):
+    if op == 'and':
+        expr = []
+        for x in a1, a2:
+            if isinstance(x, ast.BoolOp) and isinstance(x.op, ast.And):
+                expr.extend(x.values)
+            else:
+                expr.append(x)
+        return ast.BoolOp(ast.And(), expr)
+    elif op == 'or':
+        expr = []
+        for x in a1, a2:
+            if isinstance(x, ast.BoolOp) and isinstance(x.op, ast.Or):
+                expr.extend(x.values)
+            else:
+                expr.append(x)
+        return ast.BoolOp(ast.Or(), expr)
+    else:
+        return (op, a1, a2)
+
+def dump(bytecode):
+    op_stack = []
+    expr_stack = []
+    value_stack = []
+    reduce = defaultdict(int)
+    push = defaultdict(int)
+    rindex = dict()
+    retired = set()
+    i = 0
+    for inst in bytecode:
+        addr = inst.offset
+        op = inst.opname
+        arg = inst.argval
+        #print(addr, op, reduce[addr], push[addr], rindex.get(addr, ""))
+        if reduce[addr]:
+            if push[addr]:
+                if reduce[addr] != push[addr]:
+                    print("stack mismatch at %s: %d != %d", addr, reduce[addr], push[addr])
+            stash = []
+            assert len(expr_stack) == len(op_stack), (expr_stack, op_stack)
+            if push[addr]:
+                expr = value_stack.pop()
+                j,k = i,i
+                i += 1
+            else:
+                stash = [op_stack.pop()]
+                j,k,expr = expr_stack.pop()
+            r = rindex[addr]
+            while not j <= r <= k:
+                j2,k2,a2 = j,k,expr
+                j1,k1,a1 = expr_stack.pop()
+                xop = op_stack.pop()
+                expr = mkbool(xop, a1, a2)
+                j, k = j1, k2 # min(j1,j2), max(k1, k2)
+            expr_stack.append((j,k,expr))
+            op_stack.extend(stash)
+        if push[addr]:
+            _,_,top = expr_stack.pop()
+            #print(top)
+            #print(ast.dump(top, indent=4))
+            #print(ast.unparse(top))
+            value_stack.append(top)
+        if op == 'LOAD_NAME' or op == 'LOAD_GLOBAL' or op == 'LOAD_FAST':
+            value_stack.append(ast.Name(arg))
+        elif op == 'LOAD_CONST':
+            value_stack.append(ast.Constant(arg))
+        elif op == 'EXTENDED_ARG':
+            pass
+        elif op == 'STORE_NAME':
+            sys.stdout.flush()
+            assert not value_stack, value_stack
+            assert not expr_stack, expr_stack
+        elif op == 'POP_JUMP_IF_TRUE':
+            dest = arg
+            val = value_stack.pop()
+            expr_stack.append((i,i,val))
+            op_stack.append('or')
+            reduce[dest] += 1
+            rindex.setdefault(dest, i)
+            i += 1
+        elif op == 'POP_JUMP_IF_FALSE':
+            dest = arg
+            val = value_stack.pop()
+            expr_stack.append((i,i,val))
+            op_stack.append('and')
+            reduce[dest] += 1
+            rindex.setdefault(dest, i)
+            i += 1
+        elif op == 'JUMP_IF_TRUE_OR_POP':
+            dest = arg
+            val = value_stack.pop()
+            expr_stack.append((i,i,val))
+            op_stack.append('or')
+            reduce[dest] += 1
+            push[dest] += 1
+            rindex.setdefault(dest, i)
+            i += 1
+        elif op == 'JUMP_IF_FALSE_OR_POP':
+            dest = arg
+            val = value_stack.pop()
+            expr_stack.append((i,i,val))
+            op_stack.append('and')
+            reduce[dest] += 1
+            push[dest] += 1
+            rindex.setdefault(dest, i)
+            i += 1
+        elif op == 'COMPARE_OP':
+            a2 = value_stack.pop()
+            a1 = value_stack.pop()
+            if arg == '>':
+                cop = ast.Gt()
+            elif arg == '>=':
+                cop = ast.GtE()
+            else:
+                print('unknown comparator', arg)
+                cop = ''
+            if cop:
+                value_stack.append(ast.Compare(a1, ops=[cop], comparators=[a2]))
+        elif op == 'BUILD_CONST_KEY_MAP':
+            key_expr = value_stack.pop()
+            if len(value_stack) < arg:
+                print("error: BUILD_CONST_KEY_MAP: not enough expressions on stack (%d < %d)" % (len(value_stack), arg))
+            vals = value_stack[-arg:]
+            value_stack[-arg:] = []
+            assert isinstance(key_expr, ast.Constant)
+            assert len(key_expr.value) == arg
+            l = max(len(str(k)) for k in key_expr.value)
+            for k, v in zip(key_expr.value, vals):
+                print("    %s: %s%s," % (k, " "*(l-len(str(k))), ast.unparse(v)))
+            m = ast.Dict(map(ast.Constant, key_expr.value), vals)
+            value_stack.append(m)
+        elif op == 'STORE_ATTR':
+            obj = value_stack.pop()
+            val = value_stack.pop()
+            name = arg
+            #print(obj, name, val)
+            x = ast.Assign([ast.Attribute(val, name)], val, lineno=0)
+            #print(ast.unparse(x))
+        else:
+            print('unknown op', op, arg)
+
+    print(expr_stack)
+    print(value_stack)
+
+
+main()
diff --git a/extra/make_bps.py b/extra/make_bps.py
new file mode 100644
index 0000000..583359c
--- /dev/null
+++ b/extra/make_bps.py
@@ -0,0 +1,110 @@
+import zlib
+import bps.operations as ops
+
+def make_bps(source, target):
+    # This function was adapted from
+    # https://github.com/Alcaro/Flips/blob/master/libbps.cpp
+    # originally written by Alcaro, used under the GPLv3.0 license
+    sourcelen = len(source)
+    targetlen = len(target)
+    sourcepos = 0
+    targetpos = 0
+    lastknownchange = 0
+
+    yield ops.Header(sourcelen, targetlen, "")
+    while targetpos < targetlen:
+        numunchanged = 0
+        while (sourcepos+numunchanged < sourcelen and
+                targetpos+numunchanged < targetlen and
+                source[sourcepos+numunchanged] == target[targetpos+numunchanged]):
+            numunchanged += 1
+        if numunchanged > 1 or numunchanged == targetlen - targetpos:
+            yield ops.SourceRead(numunchanged)
+            sourcepos += numunchanged
+            targetpos += numunchanged
+
+        numchanged = 0
+        if lastknownchange > targetpos:
+            numchanged = lastknownchange - targetpos
+        while targetpos + numchanged < targetlen and not (
+                sourcepos + numchanged < sourcelen and
+                source[sourcepos+numchanged] == target[targetpos+numchanged] and
+                source[sourcepos+numchanged+1] == target[targetpos+numchanged+1] and
+                source[sourcepos+numchanged+2] == target[targetpos+numchanged+2]):
+            numchanged += 1
+            if sourcepos+numchanged >= sourcelen:
+                numchanged = targetlen - targetpos
+        lastknownchange = targetpos + numchanged
+        if numchanged:
+            rle1start = max(targetpos, 1)
+            while rle1start+3 < targetpos+numchanged:
+                if (target[rle1start-1] == target[rle1start+0] and
+                    target[rle1start+0] == target[rle1start+1] and
+                    target[rle1start+1] == target[rle1start+2] and
+                    target[rle1start+2] == target[rle1start+3]):
+                    numchanged = rle1start - targetpos
+                    break
+
+                if rle1start >= 2 and rle1start+4 < targetpos+numchanged:
+                    if (target[rle1start-2] == target[rle1start+0] and
+                        target[rle1start-1] == target[rle1start+1] and
+                        target[rle1start+0] == target[rle1start+2] and
+                        target[rle1start+1] == target[rle1start+3] and
+                        target[rle1start+2] == target[rle1start+4]):
+                        numchanged = rle1start - targetpos
+                        break
+                rle1start += 1
+            assert numchanged >= 0, numchanged
+            if numchanged:
+                yield ops.TargetRead(target[targetpos:targetpos+numchanged])
+                sourcepos += numchanged
+                targetpos += numchanged
+            if (targetpos >= 2 and targetpos+2 < targetlen and
+                target[targetpos-2] == target[targetpos+0] and
+                target[targetpos-1] == target[targetpos+1] and
+                target[targetpos-0] == target[targetpos+2]):
+                # Two-byte RLE
+                rlelen = 0
+                while (targetpos + rlelen < targetlen and
+                       target[targetpos+0] == target[targetpos+rlelen+0] and
+                       target[targetpos+1] == target[targetpos+rlelen+1]):
+                    rlelen += 2
+                yield ops.TargetCopy(rlelen, targetpos - 2)
+                sourcepos += rlelen
+                targetpos += rlelen
+            elif (targetpos >= 1 and targetpos+1 < targetlen and
+                  target[targetpos-1] == target[targetpos+0] and
+                  target[targetpos-0] == target[targetpos+1]):
+                # One-byte RLE
+                rlelen = 0
+                while (targetpos + rlelen < targetlen and
+                       target[targetpos] == target[targetpos+rlelen]):
+                    rlelen += 1
+                yield ops.TargetCopy(rlelen, targetpos - 1)
+                sourcepos += rlelen
+                targetpos += rlelen
+
+    yield ops.SourceCRC32(zlib.crc32(source) & 0xFFFFFFFF)
+    yield ops.TargetCRC32(zlib.crc32(target) & 0xFFFFFFFF)
+
+def main():
+    import bps.io
+    import bps.apply
+    import bps.validate
+    import sys
+    with open(sys.argv[1], "rb") as f:
+        source = f.read()
+    with open(sys.argv[2], "rb") as f:
+        target = f.read()
+
+    l = list(
+        bps.validate.check_stream(
+            make_bps(source, target)))
+
+    target2 = bytearray(len(target))
+    bps.apply.apply_to_bytearrays(l, source, target2)
+    assert target == bytes(target2), "invalid patch created"
+
+    bps.io.write_bps(l, sys.stdout.buffer)
+
+main()