Victoria Hart (born 1988), commonly known as Vi Hart (/ˈvaɪ hɑːrt, ˈviː hɑːrt/), is an American mathematician and YouTuber. They describe themselves as a "recreational mathemusician" and are well-known for creating mathematical videos on YouTube. Hart founded the virtual reality research group eleVR and has co-authored several research papers on computational geometry and the mathematics of paper folding.