diff --git a/test/burningship.nas b/test/burningship.nas
index 7075059..076feff 100644
--- a/test/burningship.nas
+++ b/test/burningship.nas
@@ -7,7 +7,7 @@ var ppm = func(filename, width, height, RGB) {
     io.write(fd, "P6\n"~width~" "~height~"\n255\n");
     for(var i = 0; i<height; i += 1) {
         for(var j = 0; j<width; j += 1) {
-            io.write(fd,RGB(i,j));
+            io.write(fd, RGB(i, j));
         }
     }
     io.close(fd);
diff --git a/test/feigenbaum.nas b/test/feigenbaum.nas
index 009b8ad..66b4d2a 100644
--- a/test/feigenbaum.nas
+++ b/test/feigenbaum.nas
@@ -13,8 +13,8 @@ var ppm = func(filename, width, height, RGB) {
     io.close(fd);
 }
 
-var width = 1600;
-var height = 900;
+var width = 1920;
+var height = 1080;
 var bar = (os.platform()=="windows")?
     process_bar.bar(front:"sharp", back:"point", sep:"line", length:50):
     process_bar.high_resolution_bar(50);
diff --git a/test/juliaset.nas b/test/juliaset.nas
new file mode 100644
index 0000000..e6d387a
--- /dev/null
+++ b/test/juliaset.nas
@@ -0,0 +1,45 @@
+use std.process_bar;
+
+var ppm = func(filename, width, height, RGB) {
+    # P3 use ASCII number
+    # P6 use binary character
+    var fd = io.open(filename, "wb");
+    io.write(fd, "P6\n"~width~" "~height~"\n255\n");
+    for(var i = 0; i<height; i += 1) {
+        for(var j = 0; j<width; j += 1) {
+            io.write(fd, RGB(i, j));
+        }
+    }
+    io.close(fd);
+}
+
+var width = 1920;
+var height = 1080;
+var init_x = -0.75;
+var init_y = 0.3;
+var bar = (os.platform()=="windows")?
+    process_bar.bar(front:"sharp", back:"point", sep:"line", length:50):
+    process_bar.high_resolution_bar(50);
+var f = func(i, j) {
+    var (yMin, yMax, xMin, xMax) = (-1.35, 1.35, -2.4, 2.4);
+    var (yDel, xDel) = (yMax-yMin, xMax-xMin);
+    var (y, x) = (init_y, init_x);
+    var (y0, x0) = ((i/height)*yDel+yMin, (j/width)*xDel+xMin);
+    for(var iter = 0; iter<64; iter += 1) {
+        var (x1, y1) = ((x0*x0)-(y0*y0)+x, 2*x0*y0+y);
+        (x0, y0) = (x1, y1);
+        if ((x0*x0)+(y0*y0)>4) {
+            break;
+        }
+    }
+    var progress = (i*width+j+1)/(width*height);
+    if (progress*100-int(progress*100)==0) {
+        print(bar.bar(progress), " ", progress*100, "%          \r");
+    }
+    iter = iter>=25? 255:int(iter/25*255);
+    var c = char(iter);
+    return c~c~c;
+}
+
+ppm("juliaset.ppm", width, height, f);
+println();
diff --git a/test/mandelbrotset.nas b/test/mandelbrotset.nas
index 857b5e4..072a37d 100644
--- a/test/mandelbrotset.nas
+++ b/test/mandelbrotset.nas
@@ -7,7 +7,7 @@ var ppm = func(filename, width, height, RGB) {
     io.write(fd, "P6\n"~width~" "~height~"\n255\n");
     for(var i = 0; i<height; i += 1) {
         for(var j = 0; j<width; j += 1) {
-            io.write(fd,RGB(i,j));
+            io.write(fd, RGB(i, j));
         }
     }
     io.close(fd);