A conic theorem generalised: directed angles and applications

Abstract

Girls aged between 18 and 25 were eligible for the job, provided they looked the part and had a basic grasp of maths. From The Times, 4 November 1999, gleaned by Frank Tapson who comments 'They had to be good-with figures!'

Visual Latency Difference Determined by Two ‘‘Rotating’’ Pulfrich Techniques

“…One manifestation of this stereoeffect is the ‘‘pendulum’’ illusion, in which a pendulum swinging horizontally in a fronto-parallel plane (i.e., at right-angles to the line of sight and at eye-level) and viewed binocularly with a neutral density filter in front of one eye, appears to move in an elliptical path (see Figure 1a). More recent investigations have been directed towards the ‘‘rotating’’ Pulfrich illusion (Nakamizo, Nawae, & Nickalls, 1998; Nickalls, 1986, 1996, 2000; Nickalls, Kazachkov, Vasylevska, & Kalinin, 2002) in which a vertical rod rotating in a horizontal circular path can, under certain circumstances, appear to move back-and-forth from side-to-side (see Figure 1b).…”