The exposition continues with these somewhat more complex interferences - superimposing these drawings in twos then in threes - to observe whether they work visually, creating ambiguous undulating space or whether they remain blocked, mere pattern,or whether they oscillate between two-dimensional patterns - three or even more dimensional volumes - being read, with more familiarity, as space. Acquaintance might cultivate the eyes to see these flickering possibilities. Such superimposition is endless but here are some examples which function and some which do not.
'Investigate the interference of such systems with the parallel, divergent, straight or curved systems as in section 'Formal pattern'. by superimposing the sheets against the light.'


Fig.122. Regular sine curves superimposed on concave curves slip through each other creating a moving space.


Fig.123. Moving into three dimensions:Cycloid waves superimposed vertically and horizontally retain the ability to bulge or pulsate into concavity while some of the inter-secting convex lines lift them into unmistakable peaks or troughs. The eye shifts and flickers between possibilities always trying to see more.


Fig.124. Sets of sine curves interfered with by two diverging systems gives a schematic impression of waves tending to go off in two directions - towards two opposite pulls. Specifically water might flow in two directions. Here there is a contrast between rectilinear and curvilinear.


Fig.125. Regular sine waves float gracefully in the midst of convex and concave curves.(The convex and concave curves might add up to a twisting curve to the lower right.) They are suspended one within the other. This choice belongs to curvilinear fields permitting movement in three directions.


Fig.126. (Compare with fig.125. when twisting curves arise from the conjunction of convex and concave curves.) Sine waves ascend diagonally floating within the interferences by convex curves descending (in the direction of nature) to the lower right and bow curves, oscillate together permitting the eye to move freely.

'---/Continue the experiment with two different curvilinear systems as a sigmoid against a bow curve.---/'.


.C. This computer-drawn set of curvilinear lines oscillating against a repeated set of bow curves creates spectacular vibrations and a great ambiguity of movement. Depending on whether one concentrates on the waves or on the bow curves the distorted rectangles pulse in and out from convex to concave and back again. It shows the instability of the classic double rectangles which one can see as projecting or receding but not in transition. These computer-drawn representations can be migraine-inducing in their oscillation between concavity and convexity.