Neat pixelization

convert -adaptive-resize 10% -ordered-dither checks,16,16,16 -scale 1000% in.png out.png

-adaptive-resize 10%            # resize to 10%
-ordered-dither checks,16,16,16 # No idea, even after readin the man
                                # 16,16,16 might have to do with colors
-scale 1000%                    # scale back to orig size