Yao-Yao Graph a Spanner?

Is the Yao-Yao Graph a $t$-spanner for constant $t$? A geometric graph is a $t$-spanner (or just a spanner) if, for every pair of nodes, the shortest distance between the nodes following the edges of the graph is at most $t$ times the Euclidean distance between them. See below for the definition of the Yao-Yao graph.