LONDON_345 is an aluminium base cross series with geometric, almost sculptural styling. The series consists of harmonious variations of the five-leg base cross for office swivel chairs, four legs for conference chairs and three legs for lounge furniture. Usually, base crosses are thin-walled with an internal ribbed structure and an open underside. proroll pursued the goal of developing a solid base cross that was also closed on its underside – the decisive factor here was to achieve this without additional materials. For the derivation of the highly innovative 4-legged and even more the 3-legged version, proroll went new a new road. The architectural challenge of achieving the same load-bearing capacity with only three legs as with five could not be achieved in the classic way.