This intervention aims to transform the spatial experience of an inhospitable underpass in Zurich through the use of colour and geometry. Around the entrances, a colour field allocates space for two user groups, pedestrians and cyclists, splitting the tunnel into half. This field expands, slowly taking over the entire space, when reaching the centre of the tunnel before declining again. The interplay of tunnel and colour introduces a rhythm to the transition. The accentuated movement and the focus onto the center of the tunnel aim to facilitate orientation and ultimately security. Bettina Gerhold is a colour designer based in Zurich.