In 1960 in parallel with experiments with light and mobiles, I draw series of reliefs. At the same time, I made some of those reliefs .Sometimes I used as preference white, black and grey gouaches I painted the year before. I took back the principle of progression but this time I applied it with different levels or to the same elements (inclined plan) with 4 positions alternatively distributed to the surface. In other cases, the variation of the elements created a modulated surface. Those reliefs were first made in cardboard and wood. The light could freely play on them changing from levels and angles; then I did other experiments with little metallic plates regularly distributed, perpendicular with a white background. In this experiment the shade of light, shadow and reflections were primordial; it was a sort of trap of light. The material elements (the metallic plates) were vanishing to blend with the reflections of forms, shadows and all the variations prorogued by the different view angles. With those reliefs I experienced the implications of different elements outside the object; like the light incidence or the multiplication of the view point made possible by the displacement of the viewer.