A couple more ideas...
a) include a photocell to recharge the on-board battery with sunlight
b) incorporate food smells to correspond with colors. For example, brown bands smell like chocolate, red-and-white stripe bands smell like peppermint, green bands smell like mint, red bands smell like cinnamon
c) issue bands with national flags and symbols embedded
a) include a photocell to recharge the on-board battery with sunlight
b) incorporate food smells to correspond with colors. For example, brown bands smell like chocolate, red-and-white stripe bands smell like peppermint, green bands smell like mint, red bands smell like cinnamon
c) issue bands with national flags and symbols embedded