This is a patch for xeyes 1.2.0 so it only shows one eye.
Good for plushies displayed with xtoys.

diff --git a/Eyes.c b/Eyes.c
index aa54b1c..0f01216 100644
--- a/Eyes.c
+++ b/Eyes.c
@@ -633,10 +633,8 @@ static void repaint_window (EyesWidget w)
                 MakePresentData(w);
 #endif
 		eyeLiner (w, TRUE, 0);
-		eyeLiner (w, TRUE, 1);
 		computePupils (w, w->eyes.mouse, w->eyes.pupil);
 		eyeBall (w, TRUE, NULL, 0);
-		eyeBall (w, TRUE, NULL, 1);
 #ifdef PRESENT
                 UpdatePresent(w);
 #endif
@@ -678,7 +678,7 @@ drawEyes(EyesWidget w, TPoint mouse)
 	return;
     }
     computePupils (w, mouse, newpupil);
-    for (num = 0; num < 2; num ++) {
+    for (num = 0; num < 1; num ++) {
 	drawEye(w, newpupil[num], num);
     }
 
@@ -770,7 +770,6 @@ static void Resize (Widget gw)
 			    0, 0, w->core.width, w->core.height);
 	    XSetForeground (dpy, w->eyes.gc[PART_SHAPE], 1);
 	    eyeLiner (w, FALSE, 0);
-	    eyeLiner (w, FALSE, 1);
 	    x = y = 0;
 	    for (parent = (Widget) w; XtParent (parent); parent = XtParent (parent)) {
 	    	x += parent->core.x + parent->core.border_width;