Numa by Florence To is a study on visual behaviour and perception, in which a system of iterating wave values and randomly changing wave shapes are formed, differentiating between the mathematical and non-mathematical approach to the geometry of visual perception. The work references the interpretation of pneuma by Greek physician and philosopher Galen, denoting the ‘intervening air’ as an extension from the eye to the object that becomes an instrument in the nerve. Visual pneuma was used to describe the mechanism of vision under the influence of light in which the air undergoes a transformation making perception possible. As this was also a romanticised view of vision from a highly regarded anatomist in the Middle Ages, the theory of the ‘Visual Spirit’ was speculated assuming the optic nerve situated at the centre of the eye to be hollow.