diff --git a/Makefile b/Makefile
new file mode 100644
index 0000000..502d4d8
--- /dev/null
+++ b/Makefile
@@ -0,0 +1,19 @@
+.PHONY : all clean
+
+all : dither4.xex
+
+# sample5.s from sample5.jpg
+
+# reminder: $< is input
+#           $@ is output
+%.o : %.s
+	ca65 -v -t atari -o $@ $<
+
+dither4.xex : dither4.o
+	ld65 -v -C atari-asm-xex.cfg -o $@ $< 
+
+clean :
+	rm -f sample5.s
+	rm -f sample5.o
+	rm -f dither4.o
+	rm -f dither4.xex
diff --git a/dither4.js b/dither4.js
index 9e12618..af3202d 100644
--- a/dither4.js
+++ b/dither4.js
@@ -388,15 +388,19 @@ function decimate(input, palette, n) {
         for (let x = 0; x < line.length; x++) {
             let rgb = line[x];
             rgb = rgb.add(error.right);
-            rgb.cap();
+            //rgb.cap();
 
             // find the closest possible color
             let shortest = Infinity;
-            let pick = -1;
+            let pick = 1;
 
             for (let i = 0; i < palette.length; i++) {
                 let diff = rgb.difference(palette[i]);
                 let dist = diff.magnitude();
+                let darker = Math.min(diff.r, diff.g, diff.b) < 0;
+                if (darker) {
+                    dist **= 2;
+                }
                 if (dist < shortest) {
                     nextError = diff;
                     shortest = dist;
@@ -430,7 +434,6 @@ function decimate(input, palette, n) {
             error.blue[x] += nextError.b / 2;
             */
 
-            /*
             error.right.r = nextError.r / 2;
             error.right.g = nextError.g / 2;
             error.right.b = nextError.b / 2;
@@ -446,8 +449,8 @@ function decimate(input, palette, n) {
             error.red[x + 1] += nextError.r / 8;
             error.green[x + 1] += nextError.g / 8;
             error.blue[x + 1] += nextError.b / 8;
-            */
 
+            /*
             error.right.r = nextError.r / 4;
             error.right.g = nextError.g / 4;
             error.right.b = nextError.b / 4;
@@ -463,9 +466,20 @@ function decimate(input, palette, n) {
             error.red[x + 1] += nextError.r / 4;
             error.green[x + 1] += nextError.g / 4;
             error.blue[x + 1] += nextError.b / 4;
+            */
 
             // 442 is the 3d distance across the rgb cube
-            fitness[x] = 442 - (nextError.magnitude());
+            //fitness[x] = 442 - (nextError.magnitude());
+            //fitness[x] = 442 / (442 - nextError.magnitude());
+            fitness[x] = 255 / (256 - Math.max(nextError.r, nextError.g, nextError.b));
+            
+            /*
+            fitness[x] = Math.max(
+                255 - Math.abs(nextError.r),
+                255 - Math.abs(nextError.g),
+                255 - Math.abs(nextError.b),
+            );
+            */
         }
         return {
             output,
@@ -476,8 +490,37 @@ function decimate(input, palette, n) {
         };
     };
 
+
+    // black, red, blue, white
+    let rbw = [
+        palette256[0x00],
+        palette256[0x87],
+        palette256[0xf7],
+        palette256[0x0f],
+    ];
+
+    let rgb = [
+        palette256[0x00],
+        palette256[0x87],
+        palette256[0xc7],
+        palette256[0xf7],
+    ];
+
+    // grayscale
+    let gray = [
+        palette256[0x00],
+        palette256[0x05],
+        palette256[0x0a],
+        palette256[0x0f],
+    ];
+
+    //palette = rgb;
+    //palette = rbw;
+    //palette = gray;
+
     let start = Date.now();
     let decimated = palette.slice();
+
     while (decimated.length > n) {
         let {popularity, fitness, output} = dither(decimated);
 
@@ -489,21 +532,17 @@ function decimate(input, palette, n) {
                 continue; // keep black always
             }
             if (decimated[i].r == 255 && decimated[i].g == 255 && decimated[i].b == 255) {
-                continue; // keep white always
+                //continue; // keep white always
             }
 
-            let coolFactor = popularity[i];
-
-            /*
+            //let coolFactor = popularity[i];
 
             let coolFactor = 0;
             for (let x = 0; x < line.length; x++) {
                 if (output[x] == i) {
-                    coolFactor += fitness[x];
+                    coolFactor += fitness[x] ** 3;
                 }
             }
-            coolFactor /= Math.sqrt(popularity[i]);
-            */
 
             if (coolFactor < least) {
                 pick = i;
diff --git a/dither4.s b/dither4.s
new file mode 100644
index 0000000..5c467f8
--- /dev/null
+++ b/dither4.s
@@ -0,0 +1,23 @@
+SAVMSC = $58
+
+.code
+
+.export start
+
+.proc start
+    ; Get the framebuffer address and just write new fun values into it
+    ; x: byte to write in
+    ; y: index into the first 256 bytes of buffer
+
+    ldx #00
+outer_loop:
+    txa
+    ldy #00
+inner_loop:
+    sta (SAVMSC),y
+    iny
+    bne inner_loop
+    inx
+    jmp outer_loop
+    ; infinite loop
+.endproc