"REX", short for "Receptive Expressive ID (identification)", is a purpose-built app intended for use between an adult (parent, teacher, therapist, etc.) and a client (kiddo, student, patient, etc.). REX is a digital substitute for expensive flashcards that cost hundreds of dollars. Not to mention, you will eliminate hours of time-consuming materials preparation. For example, you can select a visual category (e.g. - actions, animals, colors, common items, community helpers, food, furniture, numbers, etc.) and easily customize your visual collection from one up to twelve subjects. There is a built in shuffle button designed to randomly scramble your custom visual collection testing your client's ability to track and follow. For Receptive Identification, REX will challenge your client to visually identify the subject you verbally call out. For Expressive Identification, REX will challenge your client to verbally identify the subject you visually call out. You can adjust your collection and/or switch categories anytime. Then shuffle and repeat as many iterations is you like.