by steps
000000 000000
000000
ffff00 ffff00
ffff00
00007f 00007f
00007f
0000ff 0000ff
0000ff
007f00 007f00
007f00
007f7f 007f7f
007f7f
f0f00f f0f00f
f0f00f
007fff 007fff
007fff
00ff00 00ff00
00ff00
00ff7f 00ff7f
00ff7f
e2e21f e2e21f
e2e21f
00ffff 00ffff
00ffff
7f0000 7f0000
7f0000
7f007f 7f007f
7f007f
d4d42e d4d42e
d4d42e
7f00ff 7f00ff
7f00ff
7f7f00 7f7f00
7f7f00
7f7f7f 7f7f7f
7f7f7f
c6c63e c6c63e
c6c63e
7f7fff 7f7fff
7f7fff
7fff00 7fff00
7fff00
7fff7f 7fff7f
7fff7f
7fffff 7fffff
7fffff
b8b84e b8b84e
b8b84e
ff0000 ff0000
ff0000
ff007f ff007f
ff007f
ff00ff ff00ff
ff00ff
aaaa5d aaaa5d
aaaa5d
ff7f00 ff7f00
ff7f00
ff7f7f ff7f7f
ff7f7f
ff7fff ff7fff
ff7fff
9c9c6d 9c9c6d
9c9c6d
ffff7f ffff7f
ffff7f
ffffff ffffff
ffffff
8e8e7d 8e8e7d
8e8e7d