These holograms are called Fourier Based Holograms. The resultant holograms, which showed the holographic subject covered with fringes, were considered ruined. Holography is the science and practice of making holograms. CDPs aim to address limitations of optical security features such as security holograms. These are sometimes referred to as Acoustic Holograms, Metasurfaces, Delay lines or Metamaterials. These toys featured red reflective holograms on the nose to represent the scanner. McGrew developed a process for creating holograms on mylar. The electron lithograph is also used to produce computer-generated holograms (CGH). Modern hechsherim display sophisticated holograms and seals which are hard to forge. New digital approaches such as 3D holograms and other computer-programmed expressions are developing. Her characters are tattooed or programmed with digital holograms of their sponsors. The holograms found on credit cards are examples of rainbow holograms. These systems have been used to produce holograms of live people. Her father is found by Jem and the Holograms with the help of Riot's father. Several types of holograms can be made.