Coincidentally, the Deathly Hallows has a similar parallel to the Imperial Regalia of Japan, which consists of the three sacred treasures: the sword (representing valour like the Elder Wand), the mirror (representing wisdom like the Cloak of Invisibility), and the jewel (representing benevolence like the Resurrection Stone).

In optical camouflage, the use of retro-reflective material is critical because it can be seen from far away and outside in bright sunlight — two requirements for the illusion of invisibility. Hiding a realistic object using a broadband terahertz invisibility cloak by Fan Zhou, Yongjun Bao, Wei Cao, Colin Stuart, Jianqiang Gu, Weili Zhang, and Cheng Sun. Scientific Reports 1 2011. Invisibility Cloaks had existed since the 13th century, with typical Invisibility Cloaks having been available since at least the 20th century. The Invisibility Cloak first made its appearance in Harry Potter and the Philosopher’s Stone, now you can own your very own Wizarding World-inspired garment that will make it look like anyone or anything has disappeared before your eyes. The Invisibility Cloak, developed by Wow! Stuff in collaboration with Warner Bros. Consumer Products, allows you to recreate iconic scenes from the Harry Potter films. Harry and Luna used it to view the statue of Ravenclaw with her diadem in the Ravenclaw Tower. [35]Used his father's cloak many times throughout his years at Hogwarts. He received it from Albus Dumbledore in 1991 as an anonymous Christmas present. [1] I mean to say, it is not a travelling cloak imbued with a Disillusionment Charm, or carrying a Bedazzling Hex, or else woven from Demiguise hair, which will hide one initially but fade with the years until it turns opaque. We are talking about a cloak that really and truly renders the wearer completely invisible, and endures eternally, giving constant and impenetrable concealment, no matter what spells are cast at it." — Xenophilius Lovegood describing the Cloak of Invisibility [src] Harry was hidden underneath the Cloak after the trio escaped the Wedding of William Weasley and Fleur Delacour and during the Luchino Caffe Duel on the same night. [27] However, cloaking a human-sized object at visible wavelengths appears to have low probability. [15] Indeed, there appears to be a fundamental problem with these devices as "invisibility cloaks": [16]

The trio went under the Cloak to the Third Floor Corridor when they saved the Philosopher's Stone. [14] Smolyaninov, Igor et al. "Electromagnetic cloaking in the visible frequency range." University of Maryland Department of Electrical and Computer Engineering. Dec. 10, 2007. (Oct. 13, 2009) http://arxiv.org/ftp/arxiv/papers/0709/0709.2862.pdf Once this deed was accomplished, Harry replaced the wand in the tomb of Albus Dumbledore. His mindset was that if he could die of natural causes without passing the wand to an heir, the wand's power, and, therefore, its history of bloodshed, would be gone forever.The Elder Wand, ' he said, and he drew a straight vertical line on the parchment. 'The Resurrection Stone, ' he said, and he added a circle on top of the line. 'The Cloak of Invisibility, ' he finished, enclosing both line and circle in a triangle, to make the symbol that so intrigued Hermione. 'Together, ' he said, 'the Deathly Hallows. '" — Xenophilius Lovegood [src] First Appearance: In Harry Potter and the Philosopher’s Stone,when Harry receives it as a gift for Christmas. Not a place Harry, Ron and Hermione would want to be seen – but just the right spot to overhear Draco Malfoy making mysterious plans in Borgin and Burkes To understand why this is unique, look at how light reflects off other types of surfaces. A rough surface creates a diffused reflection because the incident (incoming) light rays scatters in many different directions. A perfectly smooth surface, like that of a mirror, creates what is known as a specular reflection — a reflection in which incident light rays and reflected light rays form the exact same angle with the mirror surface. Light Reflection and Retro-reflection During a holiday spent with his aunt at Godric's Hollow, Gellert Grindelwald met Albus Dumbledore, and with him he sparked his desire for the Hallows. [2]