Other pairs of graph types that always admit a simultaneous embedding .
That might need larger grid sizes , include a wheel graph and a cycle graph , a tree and a matching , or a pair of graphs both of which have maximum degree two .
Other pairs of graph types that always admit a simultaneous embedding , but that might need larger grid sizes , include a wheel graph and a cycle graph , a tree and a matching , or a pair of graphs both of which have maximum degree two .