diff --git a/gib-gab-gob/board.scm b/gib-gab-gob/board.scm
index dab828f..3ba1b3e 100644
--- a/gib-gab-gob/board.scm
+++ b/gib-gab-gob/board.scm
@@ -7,6 +7,10 @@
             board-display
             board-winner?))
 
+;; TODO: This board is no longer time-travel friendly!
+;; Have to decide if we go back to the old board with one actor per cell,
+;; or make a new version. Board could becom a new board containing the new mark.
+
 (define ggg-size 3) ;; tic tac toe with more than 3x3 grid?
 
 (define (make-board)