Nonadditivity of the 1-genus of a graph

The 1-genus of a graph is the smallest possible genus of an orientable surface such that the graph can be drawn on the surface so that each edge is crossed over by no more than one other edge. An example with smallest number of vertices is given showing that the 1-genus of a graph is not additive, i.e. the 1-genus of a graph does not equal the sum of the 1-genera of all its blocks.