diff --git a/README.md b/README.md
index 4b9d5d3..6dd8c9e 100644
--- a/README.md
+++ b/README.md
@@ -300,10 +300,9 @@ __Note:__ the bigger a machine, the slower it reacts to inputs because signals n
     - get_target(), get the target (immutable ref)
     - apply(), applies the action
 
-PROBLEM: apply() requires a mutable reference to the target, but it's not possible to pass it in any way. Only an
-immutable ref can be passed.
-
-SOLUTION: use an immutable reference and call as_mut on it?
+- PROBLEM: apply() requires a mutable reference to the target, but it's not possible to pass it in any way. Only an immutable ref can be passed.
+- SOLUTION: use an immutable reference and call as_mut on it?
+- thread comms: use channels?
 
 TODO: figure out where to put UI logic. We probably can't do it in parallel with the simulation, so it needs
       to be executed by the manager thread.