add an optional second hand to the clock.  this can be useful
for human-scale timing.

Reference: /n/atom/patch/applied2013/clocks
Date: Sun Oct 27 00:46:43 CES 2013
Signed-off-by: quanstro@quanstro.net

--- /sys/src/cmd/clock.c	Sun Oct 27 00:45:54 2013
+++ /sys/src/cmd/clock.c	Sun Oct 27 00:45:54 2013
@@ -3,9 +3,11 @@
 #include <draw.h>
 #include <event.h>
 
-Image *hrhand, *minhand;
+Image *hrhand, *minhand, *sechand;
 Image *dots, *back;
 
+int flags;
+
 Point
 circlept(Point c, int r, int degrees)
 {
@@ -25,7 +27,7 @@
 	static int rad;
 	static Image *im;
 	int i;
-	int anghr, angmin;
+	int anghr, angmin, angsec;
 	static Tm tms;
 	static Tm ntms;
 
@@ -36,6 +38,7 @@
 	ntms = *localtime(ntm);
 	anghr = 90-(ntms.hour*5 + ntms.min/12)*6;
 	angmin = 90-ntms.min*6;
+	angsec = 90-ntms.sec*6;
 	tm = ntm;
 	tms = ntms;
 	r = screen->r;
@@ -48,6 +51,8 @@
 	for(i=0; i<12; i++)
 		fillellipse(screen, circlept(c, rad, i*(360/12)), 2, 2, dots, ZP);
 
+	if(flags)
+		line(screen, c, circlept(c, (rad), angsec), 0, 0, 1, sechand, ZP);
 	line(screen, c, circlept(c, (rad*3)/4, angmin), 0, 0, 1, minhand, ZP);
 	line(screen, c, circlept(c, rad/2, anghr), 0, 0, 1, hrhand, ZP);
 
@@ -63,7 +68,14 @@
 }
 
 void
-main(int, char**)
+usage(void)
+{
+	fprint(2, "usage: clock [-s]\n");
+	exits("usage");
+}
+
+void
+main(int argc, char **argv)
 {
 	Event e;
 	Mouse m;
@@ -72,17 +84,32 @@
 	int key, timer;
 	int t;
 
+	ARGBEGIN{
+	case 's':
+		flags ^= 1;
+		break;
+	default:
+		usage();
+	}ARGEND
+	if(argc != 0)
+		usage();
+
 	if (initdraw(0, 0, "clock") < 0)
 		sysfatal("initdraw failed");
 	back = allocimagemix(display, DPalebluegreen, DWhite);
 
 	hrhand = allocimage(display, Rect(0,0,1,1), CMAP8, 1, DDarkblue);
 	minhand = allocimage(display, Rect(0,0,1,1), CMAP8, 1, DPaleblue);
+	sechand = allocimage(display, Rect(0,0,1,1), CMAP8, 1, 0xbbbb);
 	dots = allocimage(display, Rect(0,0,1,1), CMAP8, 1, DBlue);
 	redraw(screen);
 
 	einit(Emouse);
-	t = (30*1000);
+	if(flags)
+		t = 1000;
+	else
+		t = 30*1000;
+
 	timer = etimer(0, t);
 
 	menu.item = mstr;
--- /sys/man/1/date	Sun Oct 27 00:45:54 2013
+++ /sys/man/1/date	Sun Oct 27 00:45:54 2013
@@ -10,6 +10,9 @@
 ]
 .br
 .B clock
+[
+.B -s
+]
 .SH DESCRIPTION
 Print the date, in the format
 .PP
@@ -36,7 +39,9 @@
 the real time.
 .PP
 .I Clock
-draws a simple analog clock in its window.
+draws a simple analog clock in its window.  The
+.B -s
+option adds a second hand.
 .SH FILES
 .TF /adm/timezone/local
 .TP