The two bindings nothing was calling, found by listing rather than by reading

An audit over every public name in raylib.flan against every file that calls
one turned up draw-circle-v and load-texture-from-image with no call site at
all — bound, linked, and never once executed, which is the state the parent
commit already made a rule about. Reading the diff had not caught either.

load-texture-from-image now has the only call site it can have: sand.flan
loads brush.png a second time as an Image, mirrors it in RAM, and uploads
that. The two badges sit side by side, so a flip that did nothing or an
upload that took the unedited buffer shows as two identical sprites rather
than as nothing.

draw-circle-v fills the dot at the world cursor's centre, beside the pixel
that was already there — both Vector2 forms, so both land where the ring's
centre is rather than where an integer cast would have put them.

Still uncalled and not this lane's to invent a use for: key-released? and
mouse-button-pressed?.

sand.flan

@@ -35,6 +35,13 @@
 (defvar brush rl/Texture2D)
 (defvar brush-ok bool)
 
+;; The same sheet a second time, mirrored on the CPU before the GPU ever sees
+;; it. That is what the Image family is for, and this is its only call site:
+;; nothing headless can make a texture, so load-texture-from-image would
+;; otherwise be bound and never called, which is the same as not bound.
+(defvar brush-mirrored rl/Texture2D)
+(defvar brush-mirrored-ok bool)
+
 ;; A missing file is not a crash and not silence: LoadTexture hands back a
 ;; texture with an id of 0, every draw with it is a no-op, and the program
 ;; looks like it has a drawing bug. So it is asked and said once, here.
@@ -42,7 +49,16 @@
   (set brush (rl/load-texture "brush.png"))
   (set brush-ok (rl/texture-valid? brush))
   (unless brush-ok
-    (print-line "sand: cannot load brush.png — drawing the cursor is off")))
+    (print-line "sand: cannot load brush.png — drawing the cursor is off"))
+  ;; The other route to a texture: the file into RAM, changed there, and only
+  ;; then uploaded. An Image that failed to load has a null buffer and
+  ;; unloading it is still safe, so there is one unload and not two.
+  (let [sheet (rl/load-image "brush.png")]
+    (when (rl/image-valid? sheet)
+      (rl/image-flip-horizontal (addr sheet))
+      (set brush-mirrored (rl/load-texture-from-image sheet)))
+    (rl/unload-image sheet))
+  (set brush-mirrored-ok (rl/texture-valid? brush-mirrored)))
 
 ;; Four draws, one per shape the call comes in, because none of them can be in
 ;; the acceptance table. The cursor picks one frame out of the sheet and so
@@ -60,7 +76,13 @@
       (rl/draw-texture brush 20 50 rl/white)
       (rl/draw-texture-v brush (rl/Vector2 {:x 44.0 :y 50.0})
                          (rl/get-color (nth sim/colors sim/current-color)))
-      (rl/draw-texture-ex brush (rl/Vector2 {:x 72.0 :y 46.0}) 0.0 2.0 rl/white))))
+      (rl/draw-texture-ex brush (rl/Vector2 {:x 72.0 :y 46.0}) 0.0 2.0 rl/white)))
+  ;; The mirrored one beside them, scaled up so the flip is visible rather
+  ;; than eight pixels wide. If the two badges look the same, either the flip
+  ;; did nothing or the upload took the unedited buffer.
+  (when brush-mirrored-ok
+    (rl/draw-texture-ex brush-mirrored (rl/Vector2 {:x 110.0 :y 46.0})
+                        0.0 2.0 rl/white)))
 
 ;; ── The view ────────────────────────────────────────────────────────
 ;;
@@ -169,7 +191,10 @@
                     (rl/Vector2 {:x x :y (+ y r)}) tint)
     (rl/draw-line-ex (rl/Vector2 {:x (- x (f32 4.0)) :y y})
                      (rl/Vector2 {:x (+ x (f32 4.0)) :y y}) (f32 3.0) rl/white)
-    ;; The exact world point, one pixel of it.
+    ;; The exact world point: a filled dot, and one pixel of white on top of
+    ;; it. Both are the Vector2 forms, so they land where the ring's centre
+    ;; is and not somewhere an integer cast put them.
+    (rl/draw-circle-v p (f32 5.0) tint)
     (rl/draw-pixel-v p rl/white)
     ;; A pointer above the cursor. Counter-clockwise, because raylib culls the
     ;; other winding and draws nothing — which looks exactly like a broken
@@ -281,6 +306,7 @@
   ;; is no GPU to upload to until InitWindow has made a context.
   (load-brush)
   (defer (rl/unload-texture brush))
+  (defer (rl/unload-texture brush-mirrored))
   ;; The dev agent listens on a socket for redefinitions and hands them over;
   ;; (agent/poll) below is where they are installed. Building without --dev is
   ;; fine — nothing has cells to install into, so a module is refused on the