diff --git a/Makefile b/Makefile
index 18829b9..58f5e96 100644
--- a/Makefile
+++ b/Makefile
@@ -27,7 +27,7 @@ else
 	CXXFLAGS += -D NDEBUG -O3
 endif
 
-LDLIBS := -lm -lpthread -lscgui -lSDL2 -lcairo
+LDLIBS := -lm -lpthread -lscgui -lSDL2 -lcairo -lscerror -lrt
 
 .PHONY: all clean install
 
diff --git a/main.cpp b/main.cpp
index 471b782..9511376 100644
--- a/main.cpp
+++ b/main.cpp
@@ -14,6 +14,9 @@
 #include <libscgui.hpp>
 #include <unistd.h>
 #include <cairo/cairo.h>
+#include <signal.h>
+#include <time.h>
+#include <libscerror.hpp>
 
 const int WIDTH {700};
 const int HEIGHT {700};
@@ -33,7 +36,15 @@ void print_version() {
     std::cout << "screensaver version 1.0\n";
 }
 
+void timer_signal_handler(int /*sig*/, siginfo_t* /*si*/, void* /*uc*/) {
+    // timer_t* tmr {si->si_value.sival_ptr};
+    timer_expired = true;
+}
+
 void draw() {
+    static int x = 300;
+    static int y = 300;
+
     if (timer_expired) {
         timer_expired = false;
         sc::gui::ImageLock lock {*main_image};
@@ -44,7 +55,7 @@ void draw() {
         cairo_fill(cr);
 
         // orange rectangle
-        cairo_rectangle(cr, 300, 300, 100, 100);
+        cairo_rectangle(cr, x, y, 100, 100);
         cairo_set_source_rgb(cr, 1, 0.5, 0);
         cairo_fill(cr);
 
@@ -62,6 +73,12 @@ void draw() {
 
         // show
         main_window->show_image(*main_image);
+
+        // update
+        x++;
+        y++;
+        if (x > 400) x = 300;
+        if (y > 400) y = 300;
     }
 }
 
@@ -103,6 +120,27 @@ int main(int argc, const char * argv[]) {
         //     }
         // }
 
+        // install timer signal handler
+        struct sigaction sa;
+        sa.sa_flags = SA_SIGINFO;
+        sa.sa_sigaction = timer_signal_handler;
+        sigemptyset(&sa.sa_mask);
+        throw_if_min1(sigaction(SIGRTMAX, &sa, nullptr));
+
+        // setup repeating timer with 100 ms interval
+        timer_t timer;
+        struct sigevent sev;
+        sev.sigev_notify = SIGEV_SIGNAL;
+        sev.sigev_signo = SIGRTMAX;
+        sev.sigev_value.sival_ptr = &timer;
+        struct itimerspec ts;
+        ts.it_interval.tv_sec = 0;
+        ts.it_interval.tv_nsec = 100000000;
+        ts.it_value.tv_sec = 0;
+        ts.it_value.tv_nsec = 1;
+        throw_if_min1(timer_create(CLOCK_REALTIME, &sev, &timer));
+        throw_if_min1(timer_settime(timer, 0, &ts, nullptr));
+
         // RAII instances
         sc::gui::SDLWrapper sdl2;
         sc::gui::SDLImageWrapper sdl_image;