if (nextRoom != null && Symbol.equals(edge.getSymbol(),
nextRoom.getEdge(room.id).getSymbol())) {
// Bidirectional edge
// avoid drawing twice:
if (coords.compareTo(nextCoords) > 0) continue;
g.drawLine((int)x1, (int)y1, (int)x2, (int)y2);
double midx = (x1+x2)/2,
midy = (y1+y2)/2;