Hi all, If I have two graphs g and h with internal edge property maps, how can I make these the layers of a graph i? g = Graph(directed=False) g.add_vertex(4) g_weight = g.new_ep('int') g_layer = g.new_ep('int') g.add_edge_list([[0, 1, 2, 0], [2, 3, 2, 0]], eprops=[g_weight, g_layer]) g.edge_properties['weight'] = g_weight g.edge_properties['layer'] = g_layer h = Graph(directed=False) h.add_vertex(4) h_weight = h.new_ep('int') h_layer = h.new_ep('int') h.add_edge_list([[1, 2, 1, 1]], eprops=[h_weight, h_layer]) h.edge_properties['weight'] = h_weight h.edge_properties['layer'] = h_layer This works but is not nice and gets lengthy when layers are many: i = g.copy() # make deep copy i.add_edge_list(h.edges()) # this does not add the edge properties i.ep.weight.a[-h.num_edges():] = h.ep.weight.a # manually add the edge weight i.ep.layer.a[-h.num_edges():] = h.ep.weight.a # manually add the edge layer Is there a better way? I'm using gt 2.29 from conda-ostrokach. Many thanks Haiko