The 216 Web Color Cube
#000000#000033#000066#000099#0000CC#0000FF
#003300#003333#003366#003399#0033CC#0033FF
#006600#006633#006666#006699#0066CC#0066FF
#009900#009933#009966#009999#0099CC#0099FF
#00CC00#00CC33#00CC66#00CC99#00CCCC#00CCFF
#00FF00#00FF33#00FF66#00FF99#00FFCC#00FFFF
#330000#330033#330066#330099#3300CC#3300FF
#333300#333333#333366#333399#3333CC#3333FF
#336600#336633#336666#336699#3366CC#3366FF
#339900#339933#339966#339999#3399CC#3399FF
#33CC00#33CC33#33CC66#33CC99#33CCCC#33CCFF
#33FF00#33FF33#33FF66#33FF99#33FFCC#33FFFF
#660000#660033#660066#660099#6600CC#6600FF
#663300#663333#663366#663399#6633CC#6633FF
#666600#666633#666666#666699#6666CC#6666FF
#669900#669933#669966#669999#6699CC#6699FF
#66CC00#66CC33#66CC66#66CC99#66CCCC#66CCFF
#66FF00#66FF33#66FF66#66FF99#66FFCC#66FFFF
#990000#990033#990066#990099#9900CC#9900FF
#993300#993333#993366#993399#9933CC#9933FF
#996600#996633#996666#996699#9966CC#9966FF
#999900#999933#999966#999999#9999CC#9999FF
#99CC00#99CC33#99CC66#99CC99#99CCCC#99CCFF
#99FF00#99FF33#99FF66#99FF99#99FFCC#99FFFF
#CC0000#CC0033#CC0066#CC0099#CC00CC#CC00FF
#CC3300#CC3333#CC3366#CC3399#CC33CC#CC33FF
#CC6600#CC6633#CC6666#CC6699#CC66CC#CC66FF
#CC9900#CC9933#CC9966#CC9999#CC99CC#CC99FF
#CCCC00#CCCC33#CCCC66#CCCC99#CCCCCC#CCCCFF
#CCFF00#CCFF33#CCFF66#CCFF99#CCFFCC#CCFFFF
#FF0000#FF0033#FF0066#FF0099#FF00CC#FF00FF
#FF3300#FF3333#FF3366#FF3399#FF33CC#FF33FF
#FF6600#FF6633#FF6666#FF6699#FF66CC#FF66FF
#FF9900#FF9933#FF9966#FF9999#FF99CC#FF99FF
#FFCC00#FFCC33#FFCC66#FFCC99#FFCCCC#FFCCFF
#FFFF00#FFFF33#FFFF66#FFFF99#FFFFCC#FFFFFF
The 16 Grey Levels
#000000
#111111
#222222
#333333
#444444
#555555
#666666
#777777
#888888
#999999
#AAAAAA
#BBBBBB
#CCCCCC
#DDDDDD
#EEEEEE
#FFFFFF
The Pure Colors
#110000#001100#000011
#220000#002200#000022
#330000#003300#000033
#440000#004400#000044
#550000#005500#000055
#660000#006600#000066
#770000#007700#000077
#880000#008800#000088
#990000#009900#000099
#AA0000#00AA00#0000AA
#BB0000#00BB00#0000BB
#CC0000#00CC00#0000CC
#DD0000#00DD00#0000DD
#EE0000#00EE00#0000EE
#FF0000#00FF00#0000FF