diff --git a/docs/State-of-play.md b/docs/State-of-play.md
index f6dfec4..61cfa0c 100644
--- a/docs/State-of-play.md
+++ b/docs/State-of-play.md
@@ -1,5 +1,18 @@
 # State of Play
 
+## 20260226
+
+The bug in `member` turned out to be because when a symbol is read by the reader, 
+it has a null character appended as its last character, after all the visibly 
+printing characters. When the type string is being generated, it doesn't. I've
+fudged this for now by giving the type strings an appended null character, but
+the right solution is almost certainly to not add the null character in either 
+case — i.e. revert today's 'fix' and instead fix the reader.
+
+I've also done a lot of documentation, and I've found the courage to do some 
+investigation on the bignum bug. However, I've workeg until 04:00, which is
+neither sane nor healthy, so I shall stop.
+
 ## 20260225
 
 A productive day!
diff --git a/lisp/not-working-yet.lisp b/lisp/not-working-yet.lisp
deleted file mode 100644
index 0f3a8c2..0000000
--- a/lisp/not-working-yet.lisp
+++ /dev/null
@@ -1,6 +0,0 @@
-(set! or (lambda values
-                 "True if any of `values` are non-nil."
-                 (cond
-                   ((nil? values) nil)
-                   ((car values) t)
-                   (t (eval (cons 'or (cdr values)))))))