A useful distinction
If red and green are the only distinction between two kinds of tile, some players may struggle to tell them apart. A shape, pattern or label can carry the same information through another channel.
Put it into practice
Draw a prototype without colour and check whether the important categories still differ. Add a simple consistent cue where they do not. Test the actual combination of shape and label with users; a second cue should explain the rule, not merely add decorative visual noise.