Colour version:
CMYB — cyan, magenta, yellow, black.
Ex. 07X0: 0 % cyan, 70 % magenta, 100 % yellow, 0 % black.
Arrows
:
X0X0
70X0
30X0
00X0
03X0
07X0
0XX0
Outline colour X070
All text is in black. The background is white.