draw package provides classes for representing colors:
+--------+
| AColor |
+--------+
|
/ \
---
|
--------------------------------------------------
| | | | | |
+-------+ +-------+ +-------+ +-------+ +-------+ +-------+
| Blue | | Green | | Red | | White | | Yellow| | Black |
+-------+ +-------+ +-------+ +-------+ +-------+ +-------+
The AColor class is abstract. Its variants (subclasses) are
created with no arguments.