PH 2/1 table lamp from Louis Poulsen fits well on hallway furniture, on a side table or in a window. The shades are made of reflective, mouth-blown opal glass in three layers that direct most of the light downwards. They are shiny on the outside and have a matte, sandblasted inside that gives a soft and diffused light. The iconic three-shade system was created by Danish designer Poul Henningsen, who in collaboration with Louis Poulsen designed the first PH lamps for an exhibition in Paris on 1925-1926. He used a scientific approach, building the lamp on the basis of the logarithmic spiral, a mathematical curve that occurs in many places in nature. This gives an even distribution over the entire curve of the shade which, together with the diffuse reflection through the glass, makes for harmonious and glare-free light. The numbers of PH lamps refer to the size of the shades and the letters come from the designer's initials. There is a wide range of PH lamps to explore.