As it turns, notice the colors of the eight corners:
| color | hex code | is opposite | color | hex code |
| white | FFFFFF | is opposite | black | 000000 |
| red | FF0000 | is opposite | cyan | 00FFFF |
| green | 00FF00 | is opposite | magenta | FF00FF |
| blue | 0000FF | is opposite | yellow | FFFF00 |
This uses the Red-Green-Blue or RGB values (light)
as opposed to the red, yellow and blue values of pigments.