--- a/src/zamikongine/thing.nim	Wed Jan 11 11:55:54 2023 +0700
+++ b/src/zamikongine/thing.nim	Sat Jan 14 14:08:00 2023 +0700
@@ -1,4 +1,5 @@
 {.experimental: "codeReordering".}
+import std/times
 
 type
   Part* = object of RootObj
@@ -9,6 +10,8 @@
     children*: seq[ref Thing]
     parts*: seq[ref Part]
 
+method update*(thing: ref Thing, dt: Duration) {.base.} = discard
+
 iterator partsOfType*[T: ref Part](root: ref Thing): T =
   var queue = @[root]
   while queue.len > 0:
@@ -18,3 +21,11 @@
         yield T(part)
     for child in thing.children:
       queue.insert(child, 0)
+
+iterator allEntities*(root: ref Thing): ref Thing =
+  var queue = @[root]
+  while queue.len > 0:
+    let next = queue.pop
+    for child in next.children:
+      queue.add child
+    yield next