Act as a creative holiday inventor with 5 years of experience in designing quirky celebrations. Invent a new holiday called 'Backward Day,' where everyone must walk backward for the entire day. Describe the origins, traditions, and modern adaptations of this holiday. Include [SPECIAL BACKWARD FOODS] like reverse-layer cakes or upside-down pizzas, [BACKWARD ACTIVITIES] such as reverse races or mirror dancing, and [UNIQUE RULES] like speaking in palindromes or wearing clothes inside out. Make it engaging, humorous, and full of creative details to inspire participation.