Renault Twingo of their existing partnership, announced "Project Edison", a collaboration aimed at conceiving a shared platform for small city cars to be shared by both companies. The first cars using the platform were the third generation Twingo and the second generation Smart Forfour. Renault and Daimler invested equally during the research and development phase, with Renault subsequently specializing in the engines and Daimler in transmissions. Both companies tried to ensure a distinctive design. Renault designers took inspiration from the Renault 5. and the first generation Twingo, The car was originally launched with four colour options, as with the original Twingo. The
Latitude of the Gulf Stream and the Gulf Stream north wall index analysis was then used to find the pattern of variation common to the six longitudes. This is preferable to simple averaging of the six latitude estimates which would emphasise the eastern longitudes where the north-south movements are largest, and possibly obscure smaller but coherent north-south shifts further west. Correlation coefficients are calculated between the six time-series and the principal components are the eigenvectors of the resulting correlation matrix. (Empirical orthogonal function analysis proceeds instead from the variance-covariance matrix which again is biased to the eastern longitudes.) Each principal component is calculated as a weighted average of the standardised latitude series