diff --git a/progress.cpp b/progress.cpp
index ef6cf47..1887088 100644
--- a/progress.cpp
+++ b/progress.cpp
@@ -1,18 +1,93 @@
 #include <iostream>
-#include <libscterm.hpp>
 #include <ctime>
+#include <cmath>
+#include <libscterm.hpp>
 
-int main() {
-    sc::term term {STDERR_FILENO};
-    std::cout << term.rows() << " rows, " << term.cols() << " cols\n";
-    sleep(1);
+void show_rows_cols(const sc::term& t) {
+    std::cout << t.rows() << " rows, " << t.cols() << " cols\n";
+}
+
+void show_progress(const sc::term& t) {
     struct timespec tm;
     tm.tv_nsec = 20000000;
     tm.tv_sec = 0;
     sc::cursor_hider ch {STDERR_FILENO};
     for (int i = 0; i < 1000; ++i) {
-        term.progress(i, 1000);
+        t.progress(i, 1000);
         nanosleep(&tm, nullptr);
     }
     std::cerr << std::endl;
 }
+
+void show_hue_bar(const sc::term& t, int top) {
+    int r = top;
+    int g = 0;
+    int b = 0;
+    // red -> yellow
+    while (g <= top) {
+        t.rgbb(r, g++, b);
+        std::cerr << ' ';
+    }
+    g = top;
+    // yellow -> green
+    while (r >= 0) {
+        t.rgbb(r--, g, b);
+        std::cerr << ' ';
+    }
+    r = 0;
+    // green -> cyan
+    while (b < 6) {
+        t.rgbb(r, g, b++);
+        std::cerr << ' ';
+    }
+    b = top;
+    // cyan -> blue
+    while (g >= 0) {
+        t.rgbb(r, g--, b);
+        std::cerr << ' ';
+    }
+    g = 0;
+    // blue -> magenta
+    while (r <= top) {
+        t.rgbb(r++, g, b);
+        std::cerr << ' ';
+    }
+    r = top;
+    // magenta -> red
+    while (b >= 0) {
+        t.rgbb(r, g, b--);
+        std::cerr << ' ';
+    }
+    t.reset();
+    std::cerr << std::endl;
+}
+
+void show_hue_bars(const sc::term& t) {
+    for (int top = 1; top < 6; ++top) {
+        show_hue_bar(t, top);
+    }
+}
+
+void show_grayscale_bar(const sc::term& t) {
+    for (int i = 0; i < 23; ++i) {
+        t.grayb(i);
+        std::cerr << ' ';
+    }
+    t.reset();
+    std::cerr << std::endl;
+}
+
+int main() {
+    sc::term term {STDERR_FILENO};
+    try {
+        show_rows_cols(term);
+        show_grayscale_bar(term);
+        show_hue_bars(term);
+        show_progress(term);
+    } catch (const std::exception& ex) {
+        term.reset();
+        std::cerr << ex.what() << std::endl;
+        return EXIT_FAILURE;
+    }
+    return EXIT_SUCCESS;
+}