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diff --git a/library/demos/square b/library/demos/square
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+#!/bin/sh
+# the next line restarts using wish \
+exec wish "$0" "$@"
+
+# square --
+# This script generates a demo application containing only a "square"
+# widget.  It's only usable in the "tktest" application or if Tk has
+# been compiled with tkSquare.c. This demo arranges the following
+# bindings for the widget:
+# 
+# Button-1 press/drag:		moves square to mouse
+# "a":				toggle size animation on/off
+#
+# SCCS: @(#) square 1.7 97/02/24 16:42:31
+
+square .s
+pack .s -expand yes -fill both
+wm minsize . 1 1
+
+bind .s <1> {center %x %y}
+bind .s <B1-Motion> {center %x %y}
+bind .s a animate
+focus .s
+
+# The procedure below centers the square on a given position.
+
+proc center {x y} {
+    set a [.s size]
+    .s position [expr $x-($a/2)] [expr $y-($a/2)]
+}
+
+# The procedures below provide a simple form of animation where
+# the box changes size in a pulsing pattern: larger, smaller, larger,
+# and so on.
+
+set inc 0
+proc animate {} {
+    global inc
+    if {$inc == 0} {
+	set inc 3
+	timer
+    } else {
+	set inc 0
+    }
+}
+
+proc timer {} {
+    global inc
+    set s [.s size]
+    if {$inc == 0} return
+    if {$s >= 40} {set inc -3}
+    if {$s <= 10} {set inc 3}
+    .s size [expr {$s+$inc}]
+    after 30 timer
+}