diff --git a/dither.pyx b/dither.pyx
index fbe687c..ecf93e7 100644
--- a/dither.pyx
+++ b/dither.pyx
@@ -4,7 +4,7 @@
 cimport cython
 import functools
 import numpy as np
-# cimport numpy as np
+cimport numpy as np
 # from cython.parallel import prange
 from cython.view cimport array as cvarray
 from libc.stdlib cimport malloc, free
@@ -57,20 +57,20 @@ cdef int dither_bounds_yb(Dither *dither, int y_res, int y) nogil:
 @cython.boundscheck(False)
 @cython.wraparound(False)
 @functools.lru_cache(None)
-def lookahead_options(screen, lookahead, last_pixel_nbit, x):
-    options_nbit = np.empty((2 ** lookahead, lookahead), dtype=np.uint8)
-    options_rgb = np.empty((2 ** lookahead, lookahead, 3), dtype=np.float32)
+def lookahead_options(screen, lookahead, last_pixel_4bit, x):
+    options_4bit = np.empty([2 ** lookahead, lookahead], dtype=np.uint8)
+    options_rgb = np.empty([2 ** lookahead, lookahead, 3], dtype=np.float)
     for i in range(2 ** lookahead):
         output_pixel_nbit = last_pixel_nbit
         for j in range(lookahead):
             xx = x + j
-            palette_choices_nbit, palette_choices_rgb = \
-                screen.pixel_palette_options(output_pixel_nbit, xx)
-            output_pixel_nbit = palette_choices_nbit[(i & (1 << j)) >> j]
-            output_pixel_rgb = np.array(
-                palette_choices_rgb[(i & (1 << j)) >> j])
-            options_nbit[i, j] = output_pixel_nbit
-            options_rgb[i, j, :] = output_pixel_rgb
+            palette_choices_4bit, palette_choices_rgb = \
+                screen.pixel_palette_options(output_pixel_4bit, xx)
+            # output_pixel_4bit = palette_choices_4bit[(i & (1 << j)) >> j]
+            # output_pixel_rgb = np.array(
+            #    palette_choices_rgb[(i & (1 << j)) >> j])
+            options_4bit[i, j] = palette_choices_4bit[(i & (1 << j)) >> j]  # output_pixel_4bit
+            options_rgb[i, j, :] = palette_choices_rgb[(i & (1 << j)) >> j]  #output_pixel_rgb
 
     return options_nbit, options_rgb
 
@@ -78,8 +78,8 @@ def lookahead_options(screen, lookahead, last_pixel_nbit, x):
 @cython.boundscheck(False)
 @cython.wraparound(False)
 cdef int dither_lookahead(Dither* dither,
-        Image* image_rgb, int x, int y, unsigned char[:, ::1] options_4bit,
-        float[:, :, ::1] options_rgb, int lookahead, unsigned char[:, ::1] distances, int x_res):
+        Image* image_rgb, int x, int y, np.ndarray[np.uint8_t, ndim=2] options_4bit,
+        np.ndarray[np.float_t, ndim=3] options_rgb, int lookahead, unsigned char[:, ::1] distances, int x_res):
     cdef int xl = dither_bounds_xl(dither, x)
     cdef int xr = dither_bounds_xr(dither, x_res, x)
 
@@ -103,11 +103,10 @@ cdef int dither_lookahead(Dither* dither,
                 lah_image_rgb[i * lah_shape1 * lah_shape2 + j * lah_shape2 + k] = 0
 
     cdef float[3] quant_error
-    # Iterating by row then column is faster for some reason?
-    for i in range(xxr - x):
-        xl = dither_bounds_xl(dither, i)
-        xr = dither_bounds_xr(dither, x_res - x, i)
-        for j in range(2 ** lookahead):
+    for i in range(2 ** lookahead):
+        for j in range(xxr - x):
+            xl = dither_bounds_xl(dither, j)
+            xr = dither_bounds_xr(dither, x_res - x, j)
             # Don't update the input at position x (since we've already chosen
             # fixed outputs), but do propagate quantization errors to positions >x
             # so we can compensate for how good/bad these choices were
@@ -116,8 +115,8 @@ cdef int dither_lookahead(Dither* dither,
             # quantization error from having made these choices, in order to compute
             # the total error
             for k in range(3):
-                quant_error[k] = lah_image_rgb[j * lah_shape1 * lah_shape2 + i * lah_shape2 + k] - options_rgb[j, i, k]
-            apply_one_line(dither, xl, xr, i, &lah_image_rgb[j * lah_shape1 * lah_shape2], lah_shape2, quant_error)
+                quant_error[k] = lah_image_rgb[i * lah_shape1 * lah_shape2 + j * lah_shape2 + k] - options_rgb[i, j, k]
+            apply_one_line(dither, xl, xr, j, &lah_image_rgb[j * lah_shape1 * lah_shape2], lah_shape2, quant_error)
 
     cdef unsigned char bit4
     cdef int best
diff --git a/setup.py b/setup.py
index 1090d0b..ac9b113 100644
--- a/setup.py
+++ b/setup.py
@@ -1,9 +1,16 @@
-from setuptools import setup
+from setuptools import setup, Extension
 from Cython.Build import cythonize
+import numpy
 
 import Cython.Compiler.Options
 Cython.Compiler.Options.annotate = True
 
+extensions = [
+    Extension("dither", ["dither.pyx"], include_dirs=[numpy.get_include()])
+]
+
 setup(
-    ext_modules=cythonize(["dither.pyx"], annotate=True)
-)
+    name='dither',
+    ext_modules=cythonize(extensions),
+    script_args = ["build_ext", "--inplace"]
+)
\ No newline at end of file