\dvips \usepackage[nohug]{diagrams} \diagram{ 1 & \rTo^{\tt nats} & {\tt Stream}_{\mathbb N} \\ & \rdTo_{\langle 0, {\tt Stream}_{\mathbb N} {\tt succ} \rangle} & \dTo_{\langle {\tt head}, {\tt tail} \rangle} \\ & & {\mathbb N} \times {\tt Stream}_{\mathbb N} }