ALT A gif showing the construction of the Spiral of Theodorus. The spiral is formed by a series of right-triangles. The pattern begins a right-triangle on a coordinate plane with a height and base of 1 unit. Its vertex is on the origin and one of its shorter side lengths runs down the y-axis to (0,-1). The triangle’s third vertex is at (-1,-1). Right-triangles are then formed with each new triangle’s base the hypotenuse of the previous triangle. Each triangle has a vertex at the origin and a height of 1 unit. The 1-unit side lengths form the outer edge of the spiral as it forms in a clockwise manner around the origin. Points appear at the 90° vertex of each triangle and circles of that radius form with the centre of each circle being the origin. The triangles fade out and the circles fill in, showing several increasingly narrower coloured rings around the origin, each with the same area.